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couch near him, terrifying him with a ferocious growling if discovered a negro endeavouring to make his escape. One he stirs. They then bark at intervals to give notice to the of the Spanish dogs was sent after him. On coming up, chasseurs, till they come up and secure their prisoner. Each the negro cut him twice with his muschet,* on which the chasseur is obliged to have three dogs, though lie hunts dog seized him by the nape of the neck and secured him. with two only, and these he maintains at his own expense: He proved to be a runaway, said that he and two other he lives with his dogs, and is inseparable from them. At negroes had deserted the Maroons a few days before, and home they are kept chained, and when walking with their that the party was at a great distance from the town, but masters are never unmuzzled or slipped from their ropes, that he would conduct them to it by noon next day. except for attack. One or two small dogs called finders, In the next anecdote recorded by Dallas, the attack was whose scent is very keen at hitting off a track, accompany fatal both to the unhappy object of it and to the dog. One them. Dogs and bitches hunt equally well, and the chas- of the dogs that had been unmuzzled to drink when there seurs rear no more than will supply the required number.' was not the least apprehension of any mischief, went up to Though the breed is said not to be so prolific as the com- an old woman, who was sitting attending to a pot in which moner varieties of the dog, it is stated to be infinitely stronger she was preparing a mess. The dog smelled at it and was and hardier. It is described as of the size of the largest troublesome; this provoked her ; she took ap a stick and hound, with erect ears, which are usually cropped at the began to beat him, on which he seized on her throat, which points, with the nose rather pointed, but widening much to he would not let go till his head was severed from his body wards the kinder part of the jaw. The skin and coat, it is by his master. The windpipe of the woman being much added, are much harder than those of most dogs, and it is torn, she could not be saved. said that the severe correction which they undergo in train When there is such discrepancy it becomes interesting to ing would almost kill any other description of dog; this, ascertain what the Cuban blood-hound is really like. A however, may be doubted. There are some whose nose is dog and a bitch, said to be of the true breed, were lately more obtuse, and whose frame in general is more square, brought to this country, where, soon after their arrival, the and these it is thought have been crossed with the mastiff; bitch littered ten pups, one of them deformed. Here, at but if the bulk of the animal has been a little increased by least, the statement that the Cuban blood-hound is not so the cross, it is not considered that the mixture has added prolific as the common dog was not borne out. Some of anything to the strength, height, beauty, or agility of the these pups we have seen, and we are enabled to give a denative breed. [See Mastiff.]
scription and figure of the variety. They are shorter on Bryan Edwards, in a note to his appendix, gives a very their legs than the English variety; the muzzle is shorter, different account of these Cuban blood-hounds :- Though and the animal is altogether smaller, with less of the hound these dogs,' he observes, are not in general larger than the about it than the English blood-hound has ; the height is shepherd's dogs in Great Britain (which in truth they much about two feet; the colour generally tawny, with black resemble), they were represented as equal to the mastiff in about the muzzle, or brindled like some of the Ban-dogs. bulk, to the bulldog in courage, to the blood-hound in scent, They show great attachment, and are very gentle till seand to the grayhound in agility. If entire credence had riously provoked, and then their ferocity is alarming, been given to the description that was transmitted through the country of this extraordinary animal, it might have been supposed that the Spaniards had obtained the antient and genuine breed of Cerberus himself, the many-headed mon. ster that guarded the infernal regions.'
Dallas, who had his information from the commissioner himself, William Dawes Quarrell
, to whom his work is dedicated, gives a description and representation of one of these
[Cuban hlood-hound.lt In Cuba, the common employment of these dogs was to traverse the country in pursuit of murderers and other felons, and an extraordinary proof of their activity is recorded by Dallas, who states that the event occurred about a month before the arrival of the commissioner at the Havanna. A fleet from Jamaica, under convoy to Great Britain, passing through the Gulf of Mexico, beat up on the north side of Cuba. One of the ships, manned with foreigners, chiefly renegado Spaniards, being a dull sailer,
and consequently lagging astern, standing in with the land (Chasseur with Cuban blood-hounds.]
at night, was run on shore, the captain, officers, and the few
British hands on hoard murdered, and the vessel pluudered Spanish chasseurs with his dogs; and he relates the follow- by the Spanish renegadoes. The part of the coast on which ing instances of the strength and determined ferocity of the ship was stranded being wild and unfrequented, the the latter.
• A long straight myschet, or couteau, longer than a dragoon's şıyord, and • The party had scarcely erected their huts when the bark twice as thick, something like a flat iron bar sharpened at the lower end, of ing of a dog was heard near them. They got immediately which about eighteen inches are as sharp as a razot. The point is not unlike under arms, and, proceeding in the direction of the sound, Our drawing was taken from a dog which had not attained its full growth,
assassins retired with their booty to the mountains, intend- indigent artizan, elicited general praise ; but the extraing to penetrate through the woods to some remote settle- vagant and indiscriminate applause of Mr. Lofft may well ments on the south side, where they hoped to secure them- be considered as more injurious to Bloomfie!d's reputation selves and elude all pursuit. Early intelligence of the crime, even than such contemptuous derision as that of Byron in however, had been conveyed to the Havanna, and the hisEnglish Bards.' An edition was published in the fulassassins were pursued by a detachment of twelve of the lowing year at Leipzig. At Paris a translation, entitled . Le chasseurs del Rey with their dogs. In a few days the Valet du Fermier, was made by Etienne Allard; one was criminals were all brought in and executed, not one of them also made into Italian; and in London appeared, in 1805, being in the least hurt by the dogs when captured.
* Agricolæ Puer, poema Roberti Bloomfield celeberrimum, African Blood-hound.—On his return from Africa, the in versus Latinos redditum auctore Gulielmo Clubbe, late Colonel Denhâm, then major, presented two dogs and a LL.B., a very clever effort in imitation of the Georgics. bitch of this variety to the royal menagerie in the Tower, The fame of Bloomfield was increased by the subsequent which, under the care of the keeper, Mr. Cops, then contained publication of Rural Tales, Ballads, and Songs, Good a very choice collection of animals, recorded in that interest- Tidings, or News from the Farm, Wild Flowers,' and ing publication, The Tower Menagerie, London, 8vo. 1829. Banks of the Wye.' He was kindly noticed by the Duke The Major informed Mr. Cops that with them he hunted of Grafton, by whom he was appointed to a situation in the the gazelle, and that they displayed great cunning, fre- Seal Office; but suffering from constitutional ill-health, he quently quitting the circuitous line of scent for the purpose returned to his trade of ladies' shoemaker, to which, being of cutting off a double, and recovering the scent again with an amateur in music, he added the employment of making eåse. They would hit off and follow a scent after a lapse of Æolian harps. A pension of a shilling a day was still al. two hours from the time when the animal had been on the lowed him by the duke; yet having now, besides a wife and spot, and this delicacy of nose had not escaped observation, children, undertaken to support several other members of for they were applied to nearly the same purposes as the his family, he became involved in difficulties; and, being other varieties here mentioned, and were commonly em- habitually in bad health, he retired to Shefford in Bedfordployed in Africa to trace a flying enemy to his retreat. It shire, where, in 1816, a subscription, headed by the Duke of is well remarked in the work last above-mentioned that for Norfolk and other noblemen, was instituted by the friendsyminetry and action they were perfect models, and a regret ship of Sir Egerton Brydges, for the relief of his embarrassis expressed that, in consequence of their not having shown ments. Great anxiety of mind, occasioned by accumulated any disposition to perpetuate their race, though they had, at misfortunes and losses, with violent incessant headaches, a the time of making the observation, been three years in morbid nervous irritability, and loss of memory, reduced him England, there appeared to be no chance of crossing our at last to a condition little short of insanity. He died at pointers with this breed. We agree with the writer in think- Shefford, Aug. 19th, 1823, at the age of fifty-seven, leaving ing that this blood so introduced would be a very valuable a widow and four children, and debts to the amount of 2001., acquisition. It was remarked that, of the three in the which sum was raised by subscription among his benevolent Tower, the males were very mild, but the female was of a friends and admirers. In the following year, at the sale of very savage disposition.
his MSS., that of The Farmer's Boy,' in his own handwriting, was sold for 141.
The works of Bloomfield have been published in 2 vols. 12mo. Hazlewood Hall,' which appeared a short time before his death, has little merit in comparison with his earlier productions. His Remains, consisting of Songs, Anecdotes, Remarks on Æolian Harps, Tour on the Wye, &c., were edited by J. Weston, Esq., 1824. The • Farmer's Boy,' Wild Flowers,' with several of the · Ballads and Tales,' are his best poems; and many critics, such as James Montgomery, Dr. Nathan Drake, and Sir Egerton Brydges, have expressed the highest admiration of their chaste and unaffected beauties. The author's amiable disposition and benevolence pervade the whole of his compositions. There is an artless simplicity, a virtuous rectitude of sentiment, an exquisite sensibility to the beautiful, which cannot fail to gratily every one who respects moral excellence, and loves the delightful scenes of English country life. Those who are charmed only with lofty and obscure conceptions, or a pompous parade of words, will find nothing to their taste in the simple descriptive poetry of Robert Bloomfield.
BLOW-PIPE. The instrument to whicht his name has been applied, was originally employed by jewellers and others
in the soldering of metals on the small scale, whence it (African blood-hound.)
derives its name in the German language • Löthrohr,' from BLOOMFIELD, ROBERT, an English pastoral poet, the two words 'löthen,' to solder, and 'rohr,' a tube or the youngest of six children of George Bloomfield, a tailor pipe. When used for such purposes it is constructed of a at Honington, a village near Bury St. Edinonds in Suffolk, simple metallic tube seven or eight inches in length, the where Robert was born, December 3, 1766. Having in bore of which at the larger extremity is about one-fourth early infancy lost his father, his mother obtained a scanty of an inch in diameter, and gradually contracts as it apsubsistence for her family by keeping a little school, in which proaches the other, where it terminates in an almost capillary be himself was taught to read. Her poverty with difficulty orifice; and the instrument is formed by simply bending affording him even necessary clothing, at the age of eleven this tube at a right angle at an inch or an inch and a half he was hired in the neighbourhood as a farmer's boy; from its finer extremity. In this form it is used by the but being found too feeble for agricultural labour, he was workman to direct the Hame of a lamp on the portion of placed with a relative in London to become a shoemaker. solder to be employed, by which he is enabled to bring it With no assistance or stimulus beyond the reading of a readily and without loss of time into a state of fusion : the newspaper, and a few borrowed books of poctry, of which solder is placed on a fragment of charcoal, whieh he holds his favourite was Thomson's Seasons,
' he composed his in his left hand, and upon which the flame is made to play beautiful rural poem “The Farmer's Boy'in a poor garret, by blowing a gentle current of air against it by means of No. 14, Bell Alley, Coleman Street, whilst at work with six the pipe. or seven others, who paid each a shilling a week for their Such was its sole use until the year 1738, when, as we lodging. The MS., after being offered to, and refused by, are informed by Bergman, Antony Swab, a Swedish bergseveral London publishers, was printed under the patronage rath, or counsellor of mines, and a many of very considerable of Capel Lofft, Esq., in 1800; and the admiration it produced knowledge for his time, introduced it to the notice of the was so general that, within three years after its publication, scientific world, by employing it in determining the nature more than 26,000 copies were sold. The appearance of of the metals in the various ores and minerals which came such refinement of taste and sentiment in the person of an under his notice. Swab however wrote no work on the
subject, nor does it appear to have received any particular of finding new methods of recognising bodies, and this he attention from any one until Cronstedt proposed his system did in such detail, and conducted his operations with such of mineralogy, in which the arrangement is dependent on accuracy, that all his results may be relied upon with the the chemical composition of the minerals. It thus became greatest confidence. Nevertheless it never occurred to him to him of vital importance for the general adoption of to give a written description of his new or improved methods; his system-we may almost say for its very existence-to he gave himself however all possible trouble to instruct all possess some ready and simple means of determining the who were willing to learn, and many foreign men of science, constituents of mineral bodies, as it was evident that those who passed some time with him, have made known his offered by the slow and laborious operations of chemical great dexterity in this subject ; but no one has communianalysis could not be generally employed by mineralogists. cated a perfect knowledge of his methods. This he found in the blow-pipe, and by the employment of 'I had the good fortune, during the last ten years of the fluxes in the experiments performed with this instrument, life of this in many respects most remarkable man, to enjoy he may be considered as the founder of a new department his most intimate acquaintance. He spared himself no of the chemical science. His results are to be found in his trouble to communicate to me all the results of his expe. • System of Mineralogy,' the first edition of which was pub- rience, and I have consequently held it as a sacred duty to lished in 1758, and was translated into English by Von allow nothing of this experience and of his labours' to be Engeström in 1765; also in an essay by the latter, pub- lost.' lished in London in 1770 under the title of An Essay Such then is the origin of Berzelius's treatise, a work. towards a System of Mineralogy,' by Cronstedt, translated which must be considered as the highest authority on this from the Swedish by Von Engeström, revised and corrected subject; and as there are translations in the English, by Mendez da Costa. London, 1770.
French, and German languages, we cannot too highly reThe employment of the blow-pipe in detecting the con- commend it to the study of those desirous of obtaining a stituents of minerals being thus brought into notice, ex more intimate acquaintance with the uses to which the cited the attention of the chemists and mineralogists to the blow-pipe may be applied. The English translation is howcultivation of this branch of chemistry, and its applica- ever unfortunately taken from the first edition of the text; tion to chemical analysis and to the determination of the the title is ‘The use of the Blowpipe in Chemical Analysis, mineralogical species. In Sweden however it still appears and in the Examination of Minerals,' by J. J. Berzelius. to have been studied with the greatest success; and it is to Translated from the French of M. Fresnel, by J. G. Chilthe chemists and mineralogists of Sweden that we are dren, London, 1822. indebted for the greater portion of the information which As our limits will not allow of our entering into the dehas been received on this subject, and more particularly to scription of the phenomena presented by the different cheBergman, Gahn, and Berzelius. Bergman, after extending mical elements and minerals, when experimented on by the its limits by a series of original researches, in which he blow-pipe, we must confine ourselves to a general description investigated the properties of most of the then known of the nature of the experiments performed by this instruspecies of minerals, and by a more general application to ment, and the conclusions to which it leads in determining chemical analysis, published the results of his observations the chemical constitution of a mineral, and consequently in a treatise written in the Latin language, which appeared in recognizing to what species it belongs. For this purpose at Vienna in 1779 under the following title, * De Tubo Fer- it may be convenient to class the experiments under four ruminatorio, ejusdemque usu in explorandis Corporibus, heads :presertim Mineralibus. A translation of the above into 1. The characteristic changes produced on bodies when English will be found in the second volume of Bergman's exposed to a high temperature. •Chemical and Physical Essays,' by Dr. Cullen, London, 2. The deoxidizing effect of the flame, and the reduction 1788. Gahn, though indefatigable in his observations and of metals from their ores. experiments with the blow-pipe, and though far exceeding 3. The oxidizing effect, or the changes produced by the any of his predecessors both in the conception and execu oxygen of the air on the body. tion of his experiments, has however left no work on the 4. The action produced by the application of fluxes or resubject. As an instance of his power of detecting the pre- agents. sence of metallic bodies, we are told by Berzelius that he The first three classes are dependent on the unaided has often seen him extract from the ashes of a quarter of a action of the blow-pipe flame, and as the total effect is prosheet of paper distinct portions of copper, and that too before duced by properties peculiar to particular parts of the flame the knowledge of the occurrence of this metal in vegetables even in the cases where fluxes are employed, it becomes a was known, and therefore before he could have been led matter of great importance to possess a good knowledge of from this circumstance to suspect its presence in paper. the flame itself
, a description of which will therefore be first Although we cannot but feel regret at having received given. If a burning lamp or candle be carefully observed, no work from a man so eminently qualified to instruct on it will be found that the flame may be divided into four this subject as Gahn, still we must consider ourselves most parts, which may readily be distinguished from each other. happy that under such circumstances the loss of the know- Firstly, on the lower extremity of the flame, where it is in ledge and experience of so long and laborious a life is not contact with the wick, will be seen a blue portion, which also to be lamented. Fortunately for science, accident, as it were, made Berzelius the medium through which this inforınation was to be communicated to the world; and while his good fortune in thus having it in his power to add another to the many benefits he has bestowed on mankind cannot but be envied, it must be universally felt and acknowledged that if he has been favoured by fortune he has proved himself one of the most worthy of her favour by the manner in which he has fulfilled the task assigned to him. The assiduity of Gahn in this study, together with the circumstances to which we are indebted for the preservation of his labours, cannot be better told than in the words of Berzelius himself. “Gahn,' says he, 'was never without his blow-pipe, not even during his shortest journeys. Every new substance, or any thing with which he was not previously acquainted, was immediately submitted to an examination before the blow-pipe; and it was indeed an interesting sight to observe with what astonishing rapidity and certainty he was thus enabled to determine the nature of a body, which from its appearance and exterior properties could not have been recognised. Through this constant
Fig. 2. nabit of using the blow-pipe he was led to invent many im- extends from the wick and terminates at the points c fig. 1, provements, and to make many conveniences, which he where the boundaries of the flame assume a vertical direccould have at hand whether at home or abroad: he ex tion. The second most striking part of the flame is the amined the action of a number of re-agents, for the purpose | bright intensely luminous portion b, which rising as it were
fom out of the cup produced by the blue, ascends in the blast a sufficient length of time to ensure the necessary form of a cone. In close connexion with this cone will be effects : it is produced by inflating the mouth with air, observed a smaller one a contained within it, of a dark which is then forced through the tube by contracting the colour, and rising from the upper extremity of the wick; and muscles of the cheek, and by a little practice the blast by a very careful examination it will be found that the outer may be thus sustained for a considerable time, the prosurface of the luminous cone is bounded by a thin coating cess of respiration being unaffected, the only inconvenience of a slightly lumino flame cd, which forms the continua- arising from the fatigue of the muscles of the cheek from tion of the blue ring, and increases a little in thickness as their unusual exercise. The power of being able to perit approaches the upper extremity.
form this depends on the individual being able to keep The three cones thus enveloping each other differ not his mouth intlated while he respires. After this has been only in their appearance, but also in their temperature and learnt, some little experience will be required to enable the chemical condition. Flame, as was shown by Sir Hum- operator to regulate the strength of the blast, so as to prophrey Davy in the course of his beautiful and philosophical duce the most powerful heat, as it must be neither too inquiries into its nature, which terminated with the disco- strong nor too weak; in the first case the heat is diminished very of his safety-lamp, is gaseous matter heated to white-in its action by an excess of air, and in the second too feeble ness : its most striking properties are evidently its power of a flame is produced. communicating light and heat, and however closely these We now proceed to the experiments themselves to which may appear to be connected, the circumstances by which the blow.pipe may be applied, and we commence with those the one may be developed to its greatest extent in a flame which fall under the first class,—The changes produced is unfavourable to the production of the other. The expla- on a body when exposed to a high temperature. Of these, nation of this is simple and obvious: the heat depends on four are particularly worthy of notice .the rapidity and energy of the chemical combinations Its fusibility. taking place ; the light on the contrary on the quantity of The changes produced in its colour. the matter kept at the white heat, and on the length of The volatization of the substance under examination. time it remains in that state. If therefore into a stream of The volatization of one or more of its component parts. burning gas (to take a particular case, let it be coal gas) a When the various elements or their compounds, which jet of oxygen be conducted, the combustion will be imme- occur in a solid form at the usual temperature, for these diately rendered more rapid, the temperature of the flame alone can here be considered, are exposed to heat, there is will consequently rise, while its illuminating power dimi always evidence of a force tending to overcome that cohesion nishes, as will probably have been observed by many who of their particles to which they owe their solid form, and it have seen the oxy-hydrogen flames, where the light is de- is believed that by a sufficient degree of temperature any rived only from the strongly heated chalk, not from the body whatever might be made to pass to the state of vapour, burning gases. On applying these views to the common either immediately or through the intermediate stage of flame, the existence of the three concentric cones will be fluidity. However this may be, it is well known that the readily understood : in the exterior cone, the inflammable temperature at which such changes are effected varies with gases arising from the decomposition of the burning ma- each element, and the point which the blow-pipe first interial come in direct contact with the atmosphere, are well forms us upon is, whether the body is one of those which supplied with oxygen, and they consequently here undergo are unchanged or not at the degree of heat capable of beirg a more rapid combustion than the interior enclosed portions : produced by means of it; and according to the result we here therefore will be found the hottest points of the flame. know among what class of bodies the one under consideraThat such is really the fact may be proved experimentally, tion will be found. Nor is this mere fact the sole guide to by holding a fine iron or platinum wire across the flame, the knowledge of the body under examination; the facility when it will be found to glow most strongly in the points or difficulty with which the change is effected, the characof its emergence from the luminous cone, and by holding ters of the substance in its changed form, the appearance the wire at different elevations in the flame, it will be found it assumes on being again allowed to cool, open to us new that the portion of the outer cone immediately above c, the sources of information, and each must be carefully observed. upper ridge of the blue cup, is the point of greatest heat. Thus in some minerals the fusion is produced with ease; In the most luminous cone the combustion is slower, and in in others again it can only be effected slowly and by the the interior darker portion, the gases have not yet come into strongest heat we can produce; while ir a third case our contact with the air, and are still unchanged.
efforts will only be sufficient to round off the sharp edge of If a fine current of air be now directed into the flame by a fine fragment. means of the blow-pipe, it will assume the appearance seen But these are by no means the most important changes, in fig. 2: in the centre of the flame, and immediately pro- the relations of the elements to oxygen gas being decidedly ceeding from the orifice of the tube, a long and thin blue more interesting and instructive. When any substance portion in the position d e of the figure will be seen: this combines with oxygen gas it is said to be oxidized, and corresponds with the blue cup of the natural flame. But it when a compound of oxygen with any base loses oxygen, was in the upper edge of this cup, in which were found the it is said to be deoxidized or reduced to a lower state of points of greatest heat, and the same is true here also, with oxidation, according as it has lost the whole or a part of its this difference however, that while in the natural flame oxygen. Most bodies, and particularly all the metals, are these points were spread over a considerable circle, cc, in capable of undergoing the one or the other of these changes; the blow-pipe flame they are all collected into the one point and as by means of the blow-pipe we have it in our power to e, where their united effect is of course proportionably great. produce at pleasure the conditions under which a metal is The reason therefore of the high temperature which may liable to be oxidized, as well as those which are favourable be produced by the blow-pipe is the result of the concentra- to its reduction, should it be present in the form of an oxide; tion of the hottest points of the flame into a focus; and an- and as these changes are usually accompanied with striking other circumstance tends also to heighten this effect, that and characteristic phenomena, the blow-pipe is thus the while in the natural flame the points of greatest heat are on most powerful instrument in detecting the presence of meits outer boundaries, and are therefore rapidly robbed of tals, which may in many cases be extracted in their perfect their temperature, they here occur encased by the luminous metallic form from the smallest fragment of their ore. flame which thus protects them against the loss of tem The oxidation will be produced by holding the body perature from this cause.
before the outer extremity of the flame, where the elements The blow-pipe employed by the workman in the soldering being heated in contact with the oxygen of the air, are of metals, and constructed as was first described, cannot be placed in the most favourable circumstances for combining employed in these operations, owing to the collection of the with it. This takes place the more readily the further the water from the condensed moisture of the breath on con assay is held from the flame, provided a sufficient temtinuing the blast any time. This inconvenience is avoided perature is at the same time obtained ; nor is it necessary by making the blow-pipe of two pieces, and by interposing that this should be very great, since too great a heat is disbetween these a receptacle for retaining the water, which is advantageous, particularly when the support is of charcoal. thus prevented from entering into the finer part of the pipe This process will be best performed with a pipe of compawhere it would obstruct the current of air. In using the ratively large orifice, and when the material is kept at a blow-pipe the operator must not employ his lungs in pro- low red heat. ducing the current of air, as it would not only be detri The deoxidation or reduction requires a small orifice, and mental to his health, but he would be unable to sustain the the substance under examination should be as much as
possible surrounded by the luminous flame, by which means knife and reduced to powder in an agate mortar. This must it is cut off from contact with the atmospheric oxygen, and then be washed, by which the fine and light particles of is surrounded with a glowing combustible gas, by which it charcoal may be readily removed from the metallic particles is deprived of its oxygen. In performing this operation, which, if any be present, will be found in a pure metallic which is infinitely more difficult than that of oxidation, par- form in the mortar. The form in which the metal will be ticular attention must be paid to keep the assay constantly found depends on its fusibility and malleability: should it in the luminous flame, as the action is but little assisted possess these properties, it will be formed into small thin by the charcoal on which the substance rests. Berzelius leaves ; if not, it will be found as a metallic powder. By recommends the beginner to practice himself in the reduc- this process the operator should be aware that the metals tion of metals by fusing small grains of tin on charcoal, and antimony, bismuth, and tellurium may have escaped his to endeavour to keep it in that state without allowing its observation, from having been volatilized as soon as reduced, surface to lose the metallic glance, which it does owing to which is also always the case with selenium, arsenic, cadthe formation of the oxide, the instant it is removed from mium, zinc, and mercury, which can only be obtained by the deoxidizing flame. This operation should first be sublimation. attempted on very small fragments, as the difficulty in The borate of soda of commerce is never sufficiently pure creases with the size of the tin grains.
for these purposes, but it may readily be obtained fit for use We now come to speak of the experiments in which fluxes by solution in pure water and re-crystallization. It may be are employed, the most important of which and their uses employed either in the form of small grains, or of powder, will be briefly described. They are, carbonate of soda, borate or it may be first fused to free it from its water of crystalof soda, the double phosphate of soda and ammonia, salt- lization. The advantages of its use in the blow-pipe are petre, boracic acid, bisulphate of potash, gyps, fluor-spar, dependent on its forming a most powerful flux, by which a nitrate of cobalt, tin, iron, lead. Of these the first three only number of otherwise refractory substances may readily be are of general use, while the others are employed to test the brought into a state of fusion. It is usual, in the first place, presence of particular bodies : we shall confine our attention to endeavour to fuse a small fragment of the assay; as, if therefore to the former, as to touch upon the particular cases this process be successful, we are able to observe the phenoin which the others may be advantageous would not only lead mena taking place during the fusion better than when it is us too much into detail, but belongs more particularly to the applied in the form of a powder; and what is the most imchemical description of the properties of these bodies. portant, we see whether the assay is partially or entirely
Care should be taken that the carbonate of soda employed fusible in this flux. The principal facts to be observed are, for these experiments be free from any impurities, particu- whether the fusion is accompanied with effervescence, or larly from the sulphate. The purest which can be pur- whether it takes place tranquilly; to examine the colour of chased is the bicarbonate of commerce: if this cannot be the glass when obtained, and the changes it undergoes acobtained, a saturated solution of the ordinary carbonate cording as it is acted on by the oxidizing or reducing tlame, should be taken, through which a current of carbonic acid and also to observe whether any changes take place either must be transmitted, when the bicarbonate will be precipi- in the colour or transparency of the glass as it cools. tated in the form of fine grains, which must be washed with The phosphor salt, to use the term by which it is usually cold water and then dried. It may be tested for sulphuric designated in works on this subject, is a double salt of phosacid by means of the blow-pipe itself in the following man. phoric acid, ammonia, and soda. It is best prepared, acner:- Let a glass be formed by fusing a portion of the car-cording to Berzelius, by adding to a solution of 16 parts of bonate of soda with a small quantity of pure silica, and let chlorate of ammonia in a small quantity of boiling water the resulting glass be well acted on by the deoxidizing 100 parts of crystallized phosphate of soda : this latter must flame. If on cooling it retains its colourless condition, the then be brought also to a state of solution over the fire, after soda may be considered free from sulphuric acid, the pre- which the solution must be immediately filtered, and then sence of which would be indicated by the glass assuming a be allowed to cool slowly, when the double salt will be depoyellow passing into a hyacinth-red colour, owing to the sited as crystals. It may be considered as pure if the cryspresence of the liver of sulphur. The application of soda tals when fused give a glass, which does not become opaque answers two purposes: to determine whether the body is on cooling. The object of this salt is to enable us to try the fusible in it as a tlux, and to assist in the reduction of metals. action of a free and strong acid on the assay, which is best The soda is best applied by mixing it in powder with the obtained by this means, as on heating the ammonia is driven substance to be examined, which should also be in powder : off, and the acid with which it was combined is then at the mixture is formed into a paste by the addition of a little liberty to exercise its influence on the body tested. It is water, a small portion of which must then be placed on the therefore a powerful agent in proving the presence of the charcoal, where, after drying, it must be brought into a metallic oxides, with which it frequently forms characteristic state of fusion. It is usual for the soda, as soon as it is coloured salts; and it is also a good test for determining the fused, to be entirely absorbed by the charcoal, but it is not presence of silica in minerals, the phosphoric acid depriving on that account legs active: a continued effervescence is it of the bases with which it was combined, and presenting observed on the substance under examination, and its fusi- it in the form of a gelatinous substance. bility is indicated by the formation of a glass globule.
It now only remains once more to call the attention of all But the greatest use of soda is decidedly in promoting the our readers, who may be in any way engaged in any manureduction of metals, which it does in a most unaccountable facture dependent on the applications of chemistry, to the manner. If a small quantity of the oxide of tin be placed great advantages to be derived from the possession of some on the charcoal, a dexterous blower, at some expense of skill in the use of this little instrument. For instance, of time and trouble, will be able to obtain from it a small glo- what advantage would it be to the apothecary, in enabling bule of metallic tin. If however a little carbonate of soda him, at the cost of a few minutes, to prove the absence of be added to the oxide of tin, the reduction is effected with impurities in the medicines he purchases -- to the chemical ease and rapidity.
manufacturer, to the dyer, the miner, the assayer. Nor are The intluence of the soda in this operation is not under there any difficulties arising from the size or expense of the stood, but its action is constant; and Gahn has given the necessary apparatus; all that is most commonly necessary following process, by which the metals platinum, gold, might be conveniently carried in the pocket. Nor is the silver, molybdenum, tungsten, antimony, tellurium, bis requisite knowledge difficult of acquirement; nor need the muth, tin, lead, copper, nickel, cobalt, and iron may be ob- individual, in order to be able to employ this instrument in tained, and consequently their presence detected, whenever a manner practically useful to himself, be a scientific chethey occur in any ore.
mist: it is one thing to be able to apply a particular part of The assay is reduced to powder, and formed as before into a science, another to extend it by discoveries. a paste with the moistened soda : this must then be placed BLUBBER [See WHALE-Fishery.] on the charcoal, and submitted to the action of a good reducing flame. After some time an additional quantity of field-marshal of the king of Prussia, was born Dec. 16th,
BLÜCHER, LEBRECHT VON, prince of Wahlstatt, soda must be added, and the blast must be again renewed, 1742, at Rostock, a town near the shore of the Baltic, in the and this process must be repeated til the whole of the duchy of Mecklenburgh Schwerin. His father was a cap. assay is absorbed by the charcoal. When this is entirely tain of cavalry in the service of Hesse Cassel. At an early effected, those portions of the charcoal which have thus be- age he manifested a strong predilection for the military procome saturated with soda, must be moistened by a few drops fession: and, in opposition to the advice of his relatives, of water, and they must then be carefully removed with a
entered, in his fourteenth year, a regiment of Swedish