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in a more complete and expeditious manner than has been hitherto used. Dated Dec. 17.
John Sharren Ward, of Bruton, Somersetshire, filk-throwfler; for a machine, upon new and improved principles, for the purpose of doubling either filk, cotton, flax, hemp, worfted, yarn, or other threads. Dated December 30.
Thomas Grace, of Neat-Houfe, in the parish of Saint George, Hanover-fquare, Middlefex, whitelead-maker, for a method of, making an acid for corroding lead, and for other purposes; and allo a new method of preparing and making white-lead, either with or without the faid acid. Dated Dec. 30, 1800. Lawson Hudlefton, of Shaftefbury, Dorfetfhire, efq.; for the method of conveying boats or barges from a higher level to a lower, and vice verfa, on canals. Dated De
Account of a Method of defiroying Caterpillars on Gooseberry-Bushes; from the Prize-Elays of the Highland Society of Scotland.
Receipt for this purpofe was offered to be communicated to the fociety, by William Henderson, at Baldridge-Burn, near Dumfermline, on the 6th of February, 1795, for a fuitable reward. The propofal was referred to a subcommittee, of which Dr. Monro, profeffor of anatomy in the Univerfity of Edinburgh, was chairman; who, after making trial of the receipt, gave in their report on the 1ft of July, 1796. The receipt for the preparation, and the manner of ufing it, was in the following words:
Take one Scots pint of tobacco liquor, which the manufacturers of tobacco general fell for deftroying bugs, and mix therewith about one ounce of alum; when the alum is fufficiently diffolved, put this mixture into a plate, or other veffel wide and long enough to admit of a brush, like a weaver's brush, being dipped into it; and, as early in the feafon as you can perceive the leaves of the bushes to be in the leaft eaten, or the eggs upon the leaves (which generally happens about the end of May, and which will be found in great numbers on the veins of the leaves on their under fide), you are to take the preparation or liquor, and dip the brui into it, holding the brush towards the under fide of the bush, which is to be raised and fupported by the hands of another perfon; then, by drawing your hand gently over the hairs of the bruth, the above liquor is fprinkled, and thrown in fmall drops on the leaves: the confequence of which is, if the eggs are there, they never come forward; and, if they have already generated worms, in a minute or two after the liquor touches them, they either die, or ficken fo as to fall off the bufh, at leaft they do fo upon giving it a little fake. If, upon their thus falling off, they fhall not ap pear to be completely dead, the bufh fhould be held up, and either a little boiling water from a watering-pan thrown on them, or a bruife given them by a fpade or fhovel, or the earth where they lie turned over with a hoe. This preparation does not in the leaft injure the bushes.
The liquor here meant is gene rally not in the fame state it is extracted
tracted from the tobacco, but is mixed, by the tobacco manufacturers, with cold water, in the proportion of four or five pints of water to one of the original juice or effence. Therefore, any person who may purchase the juice itself, unmixed, muft mix it with water in the above proportion; and the quantity of alum must be about an ounce for each Scots pint of the mixture.
Dr. Monro's report was in the following words: "I obferved; along with Mr. Hamilton and Mr. Gordon, (two other gentlemen of the committee) and two gardeners who were present, that fuch caterpillars as were wetted by the liquor Mr. Henderson employs, were killed in a very few minutes; and the experiment has been repeated by my own gardener, with the fame effect. I have likewife found, that it kills a kind of green fly, which is very hurtful to the leaves of plumb-trees and other fruit-trees. It has been very generally known, that the fmoke and the juice of tobacco were pernicious to different kinds of infects and worms; but it has not, fo far as I know, been employed in Mr. Henderfon's manner; and, as this has the advantage of not hurting the leaves, nor the fruit, I confider it as an useful and material improvement, and well entitled to a moderate premium."
wine, vinegar, and several other liquors, rendered it neceffary to take into confideration the two following circumftances respecting that metal:
First. To determine what degree of purity pewter fhould poffefs, in order to render it fit for the ufes above-mentioned, without any risk to health.
Secondly. To discover fome fimple and eafy means by which the quality of pewter might at any time be afcertained, without injury to the veffels made of it.
In confequence thereof, MM. Legendre, Gattey, and Coquebert, members of the council of weights and measures, propofed, fome months ago, to the government, that a plan of inquiry fhould be undertaken, in conjunction with MM. Gillet, Lefevre, and Lelievre, members of the council of mines, by which the folution of the above queftions might be accomplished.
Thefe commiffioners defired to be affifted by MM. Foureroy, Vauquelin, and Dillon; and, after a great number of delicate experiments, made with the greatest care, by the united labour of the forementioned gentlemen, many new and interest ing facts were afcertained, which have ferved to fix the opinion of the government, with refpect to those points which were the objects of this inquiry.
The experiments of the above gentlemen have proved,
Firft. That tin is more eafily dif folved than lead, and is diffolved fooner than lead, by the action of wine, or of vinegar.
Secondly. That lead is not fenfi. bly oxidated by the above liquors, except at the line of contact of the air and the liquor: confequently, Cc 2
a very small furface only is affect ed.
Thirdly. That the moft green and four wine that could be met with in the neighbourhood of Paris, diffolved only an infenfible quantity of lead, after having remained from eight to ten days in veffels made of pewter which contained 18 per cent. of lead.
Fourthly. That nearly the fame effect took place when vinegar was ufed inftead of wine; and that no fenfible appearances were produced by re-agents, except when the pewter of the vessel in which the vinegar had flood contained more than 18 per cent. of lead. In proportion as the vinegar becomes faturated with pewter, a fmall quantity of tartrite of lead is depofited; but the quantity of this depofit is extremely small, even when the velfels in which the vinegar ftands are of great diameter, and have a large internal furface.
Fifthly. When red wine remains in pewter veffels, it lofes its colour. This effect arifes from, the colouring matter being precipitated, after being combined with oxide of tin. The precipitate does not appear to contain any lead; yet the tafte of the bad wine, made use of in this experiment, became more fweet. There is, however, reafon to think, that this effect arofe rather from the precipitation of the colouring matter, and the faturation of a part of the acid of the wine, than from any lead contained therein.
From the above experiments, the commiffioners concluded, that veffels made of a mixture of tin and lead might be used for wine, and for vinegar, provided the proportion of the latter metal was not more than from 15 to 18 per cent. and that no
injury to health need be apprehended, from the use of veffels made within the above-mentioned proportions.
The object of the fecond part of this inquiry was, to find fome means by which the proportion of lead in pewter might easily be determined. The hydroftatic balance is well known to offer the fureft method of doing it; yet this method has not been made ufe of in any country. Inftead of it, various conjectural methods were adopted, such as, the appearance of the meta!, the flexibility of it, or other circumftances equally uncertain. A chymical analyfis is capable of afcertaining the matter with precifion: but fuch an analysis would be tedious and troublefome; befides which, it would be neceffary to take away a part of the veffels themselves, for the purpose of analyfis. An examination of the fpecific gravity has none of thefe inconveniences; but, in order to make it the bafis of legal determination, it was neceflary to alcer tain, by experiment, in what manner tin and lead, when united in various proportions, were affected in this refpect. It had been fufpected, that mixtures of these two metals did not poflefs exactly that fpecific gravity which they would appear to do by calculating upon that which each of them poffefs feparately. But, was their fpecific gravity augmented or diminished? did the two metals penetrate each other when mixed, or was there, on the contrary, a greater vachton between their particles than existed in them when feparate? These were queftions which experiments only could determine: for, the opinions of the philofophers who have writ
ten on that fubject were not uniform. Kæftner, Haufen, Hahn, and even Lavoifier, believed that penetration took place. The fpecific gravity refulting from the mixture, fays the latter, exceeds very much that which would be obtained by computing the volumes and maffes. Kraft alone, in the Peterburgh Tranfactions, vol. XIV. maintained the opinion of dilatation; but he refted it only on one fingle fact. Thole who have treated this fubject in other places, particularly in the Memoirs of the Academy of Stockholm, have confined themselves to calculations, without making any experiments; it became therefore neceffary, above all things, to have recourse to observation,
Tin and lead, in the moft perfect ftate of purity they could be procured, were mixed together in various proportions; great care was
taken that they should be well mixed together, and alfo that no cavity or air-bubble fhould be left in the mixture. Three different feries of these mixtures were made; and, upon being tried in the hydrostratic balance, the refults were found to be as follows:
Mixtures of tin and lead were found to poffefs lefs fpecific gravity than would have been obtained by calculation; confequently, thefe two metals, inftead of penetrating each other refpectively, increase in bulk, when mixed together.
The following is the law of that increase, as far as it can be deduced from the above experiments.
When the quantity of lead was in the proportion of nine-tenths of the whole, the bulk of the mixture increafed, or, in other words, the fpecific gravity diminished, twentyfix thoufandth parts.
8 parts of lead and 2 of tin, increased in bulk 40 thousandth part
these metals is mixed with the pewter uled in commerce; for fome of them injure the colour, or the quality of the metal; and others are at least as dear as lead or tin, confequently no advantage can be gained by using them.
Receipt for defroying the Vermin which infeft Plants; from the French of Baftien's Gardener's Year.
AKE of black foap two pounds of and a half, flower of fulphur two pounds and a half, mushrooms of any kind two pounds, water 60 pints. Divide the water into two equal parts, and put one half in a barrel with the foap and the mufhrooms, after having bruifed them a little. The other half of the water is to be boiled in a cauldron with the fulphur inclofed in a bag, and fixed to the bottom of the cauldron by a ftone or other weight. During an ebullition of about 20 minutes, the bag of fulphur must be stirred about with a stick, the better to impregnate the water. By augmenting the quantity of ingredients, the effects will be more fenfible. The water, that has been thus boiled, muft then be poured into the barrel, and daily ftirred up with a stick, until it ac quires the higheft degree of ranknefs: care being always taken to ftop up the barrel after the water has been stirred.
This compofition is to be (prinkled, or injected on the plants infefted; and it will, at the firft injection, deftroy the greater number of the infects: but it will require frequent repetitions to kill thofe which live under ground; efpecially the ants; to exterminate them, from
HE ufe of the flail is fcarce
wheat is trodden out in the field by horfes upon the bare fandy foil, with which much of it gets incorporated, and afterwards is feparated from it by fieves, or fome other means that anfwer the purpofe; the confe quence of this is, that a confiderable quantity of duft adheres to the furface of the grain, and infinuates itself into the groove on one fide of it, fo that no art can entirely clear it away; and thence I am told millers are unable to make superfine flour from Virginian wheat; and on that account, that it bears a price, inferior to what the quality would otherwife demand. A weevil, or fome other infect, greatly infefts the wheat of this ftate when in the ftraw, which makes it neceflary to tread it out as foon as poffible after harveft; and this is frequently attended with inconvenience and loss. In unloading the wheat of this flate from fhipboard, or otherwife working among it in the granaries, the people employed are frequently fo affected with a pricking or nettling on the fkin, as to be unable to go