known to every experienced gardener, that a plant under the most skilful management, does not readily recover its former vigour, when it has been injured by exposure, for a few hours, to a temperature much below that to which it has been previously accustomed. It frequently happens in this climate, when the blossoms of our fruit trees are just expanding, that a very warm day succeeds a night whose temperature has been some degrees below the freezing point of water. In such a day the evaporation from the unfolding leaves and blossoms will be greatly increased by the agency of heat and light, whilst the supply of nourishment is in a great measure cut off by the ill effects of the preceding night. The blossoms will nevertheless unfold themselves, but will be unproductive, from the want of due nourishment; whilst the hazy appearance of the air, which almost always accompanies such weather in the spring, will induce the gardener unjustly to infer that the ill effects he observes have arisen from some quality in the air (distinct from excess of heat and cold), which he denominates a blight.

The best defence against this kind of weather for wall trees, that I believe has yet been tried, is a covering of a double and triple net; for by this the tree is in some degree protected from frost; and the excess of evaporation, in the succeeding day, is in a very considerable degree prevented. Lightning is supposed by many to be very highly injurious to the blossoms of trees; but I believe that the ill effects which appear sometimes to accompany it may be more justly attributed to excessive heat. The careful gardener often covers his trees with mats, or

something of this kind; and by al most totally depriving the trees of light, creates that blight which he is anxious to exclude.

As the blossoms of every tree are formed during the preceding sum mer and autumn, they will evidently be more perfect in proportion as those seasons have been favourable, and as the management of the gar dener has been judicious; and as the power of bearing unfavourable weather will be proportional to their vigour, and to the maturity of the annual wood, through which the sap passes to support them, the gar dener should be (though he rarely is) extremely attentive to keep his trees in such a state, and the brancl.es at such distances from each other, that they may receive the greatest possi ble benefit from the portion of light and heat which our shadowy climate affords them. It frequently happens in pruning, that too much bearing wood is left on the tree. Every gardener ought to know, that where a hundred fruits are a sufficient crop for a tree, he has a better chance to obtain that hundred from one thou sand blossoms, to which the whole nourishment of the tree is directed, than when the same quantity of nourishment has to support a hun dred thousand.

In standard fruit trees, where no advantages can be derived from covering them, much may be done by the judicious application of the pruning knife. The branches of a tree of this kind ought to be much thinned towards their extremities, so that the light may be admitted into the centre of the tree; but the internal parts of it should never be so thin as to admit of a free current of air through it. When a tree has been properly pruned, blossoms and

TH

HE mode in which I conceived fresh water might be preserved sweet, was merely by keeping it in vessels of which the interior lining at least should be of such a substance as should not be acted upon by the water, so as to become a cause of contamination. Accordingly, on board two ships, the greater part of the water was kept, not in casks, but in cases or tanks, which, though they were made of wood, on account of strength, were lined with metallic plates, of the kind manufactured by Mr. Charles Wyatt, of Bridge-street, under the denomination of tinned copper-sheets; and the junctures of the plates or sheets were soldered together, so that the lightness of the cases depended entirely on the lining, the water having no where access to the wood. The shape of these cases was adapted to that of the hold of the ship, some of them being made to fit close under the VOL. XLIV.

platform, by which means the quantity of water stowed was considerably greater than could have been stowed, in the same space, by means of casks; and thereby the stowageroom on board ship was very much increased.

The quantity of water kept in this manner on board each ship, was about forty tons, divided into sixteen tanks; and there was likewise, on board each of the ships, about thirty tons stowed in casks as usual.

As the stowing the water in tanks was considered as an experiment, the water in the casks was used in preference; that in the tanks being reserved for occasions of necessity, excepting that a small quantity of it was used occasionally for the purpose of ascertaining its purity, or when the water in the casks was deemed, when compared with that in tanks, too bad for use.

The water in thirteen of the tanks, on board one ship, and in all the tanks on board the other, was always as sweet as when first taken from the source; but in the other three of the tanks, on board one ship, the water was found to be more or less tainted as in the casks. This difference, however, is easily accounted for, by supposing that the water of these tanks was contaminated before it was put into them; for, in fact, the whole of the water was brought on board in casks, for the purpose of filling the tanks, and no particular care was taken to taste the water at the time of taking it on board.

After the water kept in this manner had remained on board a length of time, which was deemed sufficient for experiment, it was used out, and the tanks were replenished as occasion required: but in some

3 E

of

of the tanks, on board one ship at least, the original water had remained three years and a half, as appears by the certificates herewith enclosed. About twenty-five gallons of the water, which had renrained this length of time in the ship, are sent to the society, in two vessels made of the same sort of tinned copper with which the tanks were lined.

A certificate from captain Wm. Bolton, commander of the said vessel, dated Sheerness, 28th of June 1800, accompanied this letter, stating that the water delivered to the society was taken from a tank holding about 700 gallons, and which his predecessor, captain Portlock, had informed him had been poured into the tank in December 1796, except about thirty gallons added in 1798, and had remained good during the whole time.

The signatures to the above accounts were certified, on the 28th of June 1800, by the rev. C. Thee, minister of Sheerness.

In a letter, dated January 27, general Bentham also states, that the water which had been preserved sweet on board his majesty's sloops Arrow and Dart, and of which he had sent specimens to the society, was taken from the well of the king's brewhouse at Weevil, from whence ships of war, lying at or near Portsmouth, are usually supplied with water for their sea-store, as well as for present use,

geur, a diving boat, lately discovered by Mr. Fulton, an American:

"I have," says he, "just been to inspect the plan and section of a nautilus, or diving boat, invented by Mr. Fulton, similar to that with which he lately made his curious and interesting experiment at Havre and Brest.

"The diving boat, in the construction of which he is now enr ployed, will be capacious enough to contain eight men, and provisions enough for twenty days, and will be of sufficient strength and power to enable him to plunge 100 feet under water, if necessary. He has contrived a reservoir for air, which will enable eight men to remain under water for eight hours. When the boat is above water, it has two sails, and looks just like a common boat. When she is to dive, the masts and sails are struck.

"In making his experiments at Havre, Mr. Fulton not only remained a whole hour under water with three of his companions, but kept his boat parallel to the horizon at any given depth. He proved that the compass points as correctly under water as on the surface, and that while under water, the boat made way at the rate of half a league an hour, by means contrived for that purpose.

"It is not twenty years since all Europe was astonished at the first ascension of men in balloons: perhaps in a few years they will not be less surprised to see a flotilla of diving boats, which, on a given signal, shall, to avoid the pursuit of an enemy, plunge under water, and rise again several leagues from the place where they descended.

"The invention of balloons has hitherto been of no advantage, be

cause no means have been found to direct their course. But if such means could be discovered, what would become of camps, cannon, fortresses, and the whole art of war? "But if we have not succeeded in steering the balloon, and even were it impossible to attain that object, the case is different with the diving boat, which can be conducted under water in the same manner as upon the surface. It has the advantage of sailing like a common boat, and also of diving when it is pursued. With these qualities it is fit for carrying secret orders, to succour a blockaded port, and to examine the force and position of an enemy in their own harbours. These are sure

and evident benefits, which the diving boat at present promises. But who can see all the consequences of this discovery, or the improvements of which it is susceptible? Mr. Fulton has already added to his boat a machine, by means of which he blew up a large boat in the port of Brest; and if, by future experiments, the same effect could be produced on frigates or ships of the line, what will become of maritime wars, and where will sailors be found to man ships of war, when it is a physical certainty, that they may every moment be blown into the air by means of a diving boat, against which no human foresight can guard them?"