give such persons as have not had an opportunity of examining them, some idea of the general appearances which they actually present.

on

"It appears from Mr Griffith, that each of the four bogs included in the subject of his report, is a mass of the peculiar substance called peat, of the average thickness of 25 feet, no where less than 12, nor found to exceed 42; this substance varying materially in its appearance and properties, in proportion to the depth at which it lies the upper surface, covered with moss of various species, and to the depth of about ten feet composed of a mass of the fibres of different vegetables in different stages of decomposition proportioned to their depth from the surface, generally, however, too open in their texture to be applied to the purposes of fuel: below this, generally lies a light blackish-brown turf, containing the fibres of moss still visible, though not perfect, and extending to a further depth of perhaps ten feet under this. In the instance exhibited in the section at the close of Mr Griffith's report, are found small branches and twigs of alder and birch; but we do not understand him as being of opinion that such is by any means generally the case. At a greater depth the fibres of vegetable matter cease to be visible, the colour of the turf becomes blacker, and the substance much more compact, its properties as fuel more valuable, and gradually increasing in the degree of blackness and compactness proportionate to its depth. Near the bottom of the bog it forms a black mass, which, when dry, has a strong resemblance to pitch, or bituminous coal, and having a conchoidal fracture in every direction, with a black shining lustre, and susceptible of receiving a considerable polish. Im mediately below this lower stratum there is generally found a thin stratum of yellow or blue clay, varying in thick

ness from one to six feet; in some places the peat rests on a thinner stratum of yellowish white marl, containing upon an average about 60 per cent. of calcarious matter. This stratum of clay in this district universally rests on a solid mass of clay and limestone gravel mixed together, and extending to an unknown depth.

"We should further consider the peat moss as partaking in its general nature of the property of sponge, completely saturated with water, and giving rise to different streams and rivers for the discharge of the surplus waters which it receives from rain or snow. These streams in this district almost universally have worn their channels through the substance of the bog down to the clay or limestone gravel underneath, dividing the bog into distinct masses, and presenting in themselves the most proper situations for the main drains, and which, with the assistance of art, may be rendered effectual for that purpose.

"Such is the internal structure of the bogs in this district.

"Viewing them externally they present surfaces by no means level, but with planes of inclinations amply suf ficient for their drainage. The highest summit of any part of the bogs in this district is 298 feet above the level of the sea, taken at an ordinary springtide in the bay of Dublin; while the lowest point any where on their sur face is 84 feet lower than the highest, and therefore 214 feet above the level of the sea. It requires a mere inspec tion of the map and sections to be convinced that there is no part of these bogs from which the water may not be discharged into rivers in their immediate vicinity, and with falls adequate to their drainage; and we observe, in the instance of the bog of Timahoe, that a part of its water is discharged into the sea at Drogheda, and another part below Waterford."

REPORT MADE TO THE INSTITUTE, &c. ON WRITING INK.

From Annales de Chimie.

The object proposed by Mr Tarry in his memoir is to explain,

1. The processes employed for discharging writing from paper.

2. The processes for reviving writings which have been apparently ob. literated.

3. The best way to improve common ink.

4. Finally, the discovery of an ink which should resist all chemical agents. We shall now give an abridgment of these four articles.

ARTICLE I.

Processes for discharging Writing.

The art of discharging writing is very ancient, and the means employed are very simple. In fact, we know that it is sufficient to moisten a writ ten paper with any acid, when the writing will gradually disappear. But all the acids cannot be employed with equal success. Some leave a stain on the paper, which is not easily removed; others corrode, and render the paper unserviceable. The way to avoid these inconveniences is to make choice of an acid which shall act on the writing only, without injuring the paper, or giving it a colour_different from that which it had before it was written

It is not the same case with the nitric acid, which always takes out the ink, but soon penetrates the paper, and forms above it undulated lines of a yellow colour.

We may succeed, however, in softening both these effects, by taking the precaution to dilute the nitric acid with a sufficient quantity of water, or to wash the paper immediately after the writing has been taken out.

A mixture of the muriatic and nitric acids has but a slow action upon writing. It bleaches the paper, and does not oppose its desiccation, as when we employ the nitric acid alone.

In general, whatever be the kind of acid employed to discharge writing, it is always proper, when the operation is performed, to dip the paper in water, in order to dissolve the new combinations which the acids have formed with the particles of ink which have been discharged.

Mr Tarry, at the conclusion of this article, does not fail to observe, that China ink does not act like common ink with the acids, as its composition is quite different from that which we use for writing of all kinds. So far from the acids attacking China ink, they make it, on the contrary, of a deep black: it cannot be discharged therefore without erasing it.

ARTICLE II.

Processes for ascertaining what Writing has been substituted for something taken out, and Methods of reviving the Writing which has disappeared.

All the methods which have been 10

given for discharging writing consist, as abovementioned, in decomposing the ink, and in forcing its constituent parts to form other combinations. These combinations, being decomposed in their turn by different agents, may regain a tint, which, if it be not that of ink, at least exhibits a shade which becomes perceptible enough for ascertaining the letters and words which had been traced on the paper before it was touched by the acids.

The gallic acid is, according to the author, one of those agents, which in this case succeeds very well.

The liquid prussiate of lime also produces a good effect.

It is the same case with the alkaline hydrogenated sulphurets. But it is very certain that we never obtain any success from the employment of these agents, when we have left any acid long in contact with the writing, and particularly if we have washed the paper afterwards.

In short, we may easily conceive, that in this case the constituent parts of the ink which were combined with the acid, and had formed with it compounds soluble in water, having been taken up by this fluid, ought not to leave any trace of their existence longer; and consequently it is impossible that the agents employed for discovering them can render them visible.

It is also for this reason that the gallic acid, the liquid prussiate of lime, the alkaline hydrogenated sulphurets, and so many other re-agents which have been so much praised, can no longer be regarded as infallible me. thods for reviving writing.

ARTICLE III.

Improvement of Common Ink.

Most of the inks now in use are of a bad quality. Some are spontaneously

destroyed; others imperceptibly lose their black colour, and assume a yel low one; several, after a length of time, enter into the paper and spoil it; lastly, there are some which are first pale, and them become very black.

All these differences arise from the nature of the substances which have been employed in the making of the ink.

Convinced of the advantage of having a good article of this kind, the author commenced a series of experiments, but is forced to admit that he has not discovered any recipe superior to that which has been published by Lewis. This ink, according to our author, combines every advantage; but we must observe, that it is no more exempt than the rest from being dissolved in the acids, and in this respect it has an inconvenience which those who wish to discharge writing from paper know very well how to profit by. This circumstance, no doubt, induced M. Tarry to make some new experiments, in order to obtain an ink which should be unalterable by chemical agents; and he appears to us to have succeeded in his object.

ARTICLE IV.

Discovery of an Ink which resists the Action of Chemical Agents.

The author describes his invention in the following words:

"My ink is founded upon principles different from those of all others. It contains neither gallnuts, Brazil wood, Campeachy gum, nor any preparation of iron: it is purely vegetable, resists the action of the most powerful vegetables, the most highly concentrated alkaline solutions, and, finally, all the solvents.

"The nitric acid acts very feebly upon the writing performed with this

the

ink. The oxymuriatic acid makes it assume the colour of pigeons' dung. After the action of this last acid, the caustic alkaline solutions reduce it to the colour of carburet of iron characters of the writing nevertheless remain without alteration, and it cannot pass through these different states, except after long macerations. The principles of which it is composed render it incorruptable, and it can retain its properties many years."

The results which we obtained coincided entirely with those of the author, and we have so hesitation in saying, that his is the best we have ever seen of the kind which is called indelible ink. It is liable, however, to deposit a sediment, a disadvantage which we think might be removed by M. Tarry after a few experiments. We have tried to discharge it with all the known chemical agents, but without effect; and we think the inventor deserves the thanks of the Institute, and of the community at large.

ON THE CULTIVATION AND MANUFACTURE OF WOAD, AND ITS BENEFICIAL USE COMBINED WITH INDIGO. By Mr John Parrish.

From the Bath and West of England Agricultural Society's Papers.

Woad is a plant which, combined with indigo, gives the best and most permanent blue dye hitherto discovered. It is of great importance to our commerce, as well as to agriculture, being in nature one of the best preparers of land for a corn crop that has hitherto been discovered; and, if the land is properly chosen for it, and well mana. ged, will be found very profitable, more particularly at this time, when its price is advanced to almost an unprecedented degree; therefore I conceive,

that in rendering its cultivation and preparation better known and understood, it may be greatly beneficial to the nation.

I have the honour to be a member of the Bath and West of England Agricultural Society, where many noble and exalted characters unite their talents to promote the public benefit. And to one of its earliest and most respectable members I presume to address this information.

I have been many years a considerable consumer of woad, and have also cultivated it with much success : and though I am well experienced in the usual method of its preparation, I was induced to depart from it in consequence of the great waste of its juices in the old method of grinding and balling. But I shall endeavour to give instructions for carrying on each process, and leave those who shall un dertake it to proceed as they think best.

This plant is cultivated in different parts of England for the use of the dyers, as well as in France, Germany, &c. It is best to sow the seeds in the month of March, or early in April, if the season invite, and the soil be in condition to receive it; but it requires a deep loamy soil, and is better still with a clay bottom, such as is not subject to become dry too quickly.

It must never be flooded, but situated so as to drain its surface, that it may not be poisoned by any water stagnant upon it.

If (at any reasonable price) meadow land to break the turf can be ob tained, it will be doubly productive. This land is generally freest from weeds and putrid matter, though sometimes it abounds with botts, grubs, and snails. However, it saves much expence in weeding; and judicious management will get rid of these otherwise destructive vermin. A season of warm show.

ers, not too dry or too wet, gives the most regular crop, and produces the best woad.

If woad is sown on corn-land, much expence generally attends hoeing and weeding and here it will require strong manure, though on leys it is seldom much necessary, yet land cannot be too rich for woad. On rich land dung should be avoided, particularly on leys, to avoid weeds. Some people sow it as grain, and harrow it, in, and afterwards hoe it as turnips, leaving the plants at a distance in proportion to the strength of the land: others sow it in ranks by adrill-plough; and some dibble it in, (in quincunx form, by a stick with a peg crossways, about two or two and a half inches from the point, according to the land,) putting three or four seeds in a hole, and these holes to be from twenty inches to two feet apart, according to the richness of the land; for good land, if room be given, will produce very luxuriant plants in good seasons; but if too nearly planted, so that air cannot circulate, they do not thrive so well attention to this is necessary in every way of sowing it. I have been most successful in this last process. Woad very often fails in its crop, from the land not being in condition, or for want of knowing how to destroy the botts, snails, wire-worms, &c. that so often prey upon and destroy it, as well as from inattention to weeding, &c. Crops fail also from being sown on land that is naturally too dry, and in a dry season; but as the roots take a perpendicular direction, and run deep, such land as I have described (with proper attention to my observations) will seldom fail of a crop and if the season will admit sowing early enough to have the plants strong before the dry and hot weather comes on, there will be almost a certainty of a great produce.

If the seeds are not sown within a day

These plants are frequently destroy. ed in the germination by flies, or animalculæ, and by grubs, snails, &c. as before observed; and in order to preserve them, I have steeped the seeds with good success in lime and soot, until they began to vegetate; first throwing half a load or more of flour lime* on the acre, and harrowing it in. Then plant the seeds as soon as they break the pod, taking care not to have more than one day's seed ready ; for it is better to be too early, than to have their vegetation too strong before it is planted, lest they should receive injury; yet I have never observed any injury in mine from this, though I have often seen the shoot strong. Either harrows or rollers will close the holes. If the ground be moist it will appear in a few days; but it will be safe, and a benefit to the land, to throw more lime on the surface, when, if showers invite snails and grubs to eat it, they will be destroyed, which I have several times found; particularly once, when the leaves were two inches long, and in drills very thick and strong, but the ground was dry. When a warm rain fell, in less than two hours I found the ranks on one side attacked by these vermin, and eaten entirely off by a large black grub, thousands of which were on the leaves, and they cleared as they went, not going on until they had destroyed every leaf where they fixed. They had eaten six or seven ranks before I was called by one of my people to observe it. Having plenty of lime, I immediately ordered it in flour to be strewed along those ranks which were not begun. This destroyed them in vast numbers, and secured the remainder. Another time, having had two succeeding crops on four acres of land, I considered it imprudent to venture another. However, as the land after this appeared so clean and rich,