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USEFUL ARTS.

A Lactometer.-Mr. Fane, president of an agricultural society in G. B. has discovered a method of ascertaining the comparative value of the milk of each cow in a dairy. The principle of the invention is, that if milk is poured into a glass, and suffered to remain, the division between the cream that swims upon it, and the milk below, will be so plain and evident, that the depth of the cream may be easily measured; of course, if the milk of any cow produce more cream than that of any other cow, the difference may be correctly ascertained. This may be done in any glass vessel having upright sides: a tumbler, for instance, or, what is better, one of those glasses in which shopkeepers preserve their sugar plums, and such like wares. If the depth of milk poured into a glass, be exactly 6th inches, every 4th of an inch in depth of the cream, swimming upon it, will be equal to 2 per cent. of the amount of the whole of the milk.

The apparatus, made by Mr. Newman, consists of tubes of glass about an inch in diameter, and about 4 inches long, fixed upright in a wooden frame, each tube having a line round it, marked exactly 10 inches from the bottom. At milking time, each tube is filled up to the line with the milk of a cow; after standing twelve hours, the cream, which floats upon the milk, is measured by a scale of 10 parts to an inch. As the whole depth of the milk and cream is 10 inches, each division will represent 1 per cent. of the whole; of course, if the milk given by a cow at a meal is one gallon, or eight pints, and the thickness of the cream that floats upon it measures 14 divisions, multiply the number of pints of milk (8) by the depth of the cream (14) and the result will be, that the produce of the cream of that meal is 112, or one pint. Care must be taken to fill the tube as soon as the pail is taken from under the cow; for if any delay takes place, some of the cream will have ascended towards the top.

It is said that the milk of some cows produces no cream. It contributes, therefore, nothing to the butter, and must be an incumbrance in the churn. Such cows may be discovered by the invention of Mr. Fane, and they should be set apart for the butcher. ED. P. F.

The milk should be taken from the middle of the pail, and poured into the tube without froth, which is done by dipping a creampot below the froth, and filling the tube from thence, after having struck off the froth with the blade of a knife.

Rich milk is not white but brown, as is evident by comparing the milk of different cows when in the glass tubes; by the colour of the milk a tolerable estimate may be formed of its produce in cream. The richness of the cream may also be estimated by the colour of the cream floating in the tubes. The best Alderney cream has a yellow hue, almost as deep as the flower of the buttercup, while the cream of a Holderness cow, fed upon sour grains, is as white as chalk, as the cream separates itself. milk first becomes white, and then takes a bluish hue.

Rich

Fattening of Hogs.-A practice has recently found its way into Essex, and the other parts of England, of fattening swine, which has been found extremely beneficial: viz. that of feeding large hogs in separate stalls, so constructed that the animal can, at his pleasure, conveniently rise up or lie down, but cannot turn round. A Mr. Pattison, of Malden, observes, that they will thrive faster in this manner than in other any way. The stalls are upon an inclined plane from the head to the tail of the animal, and are cleaned out every day. Barley meal mixed with water is the food, and this farmer says, he will engage that a pig forward in flesh, weighing 70lbs. shall, in twenty-eight days, increase in weight to 140lbs.: the gain of 70lbs. live weight may be called 45lbs. dead, which at 8d. per lb. is 7s. 6d. sterl. per week. The quietness of these styes cause them to fatten more quickly, as they have only to eat and sleep.

Mr. Arthur Young supposes the most profitable method of converting grain of any kind into food for hogs, is to grind it into meal, and mix this with water in the proportion of five bushels to one hundred gallons, stirring it thoroughly several times a day for three weeks in cold weather, or for a fortnight in a warmer season, by which it will have fermented well, and become acid; till which time it is not ready to give. This mixture must always be stirred immediately before feeding, and two or three cisterns should be kept for fermenting in this manner, and giving the

grain whole, or partially ground, is so profitable, that whoever tries it once, will not, he thinks, be apt to change it. The food, of whichever kind, must be given to animals in such sufficiently short intervals, as to keep them in a state of rest: since on this principle it is that they become fat in an expeditious manner.

Method of making Leather impervious to water.-The New England fishermen preserve their boots tight against water, by the following method, which, it is said, has been in use among them above an hundred years. A pint of boiled linseed oil, half a pound of mutton suet, six ounces of clean bees wax, and four ounces of rosin, are melted and well mixed over a fire. Of this, while warm, not so hot as may burn the leather, with a brush, lay plentifully on new boots and shoes, when they are quite dry and clean. The leather is left pliant: fishermen stand in their boots, in water, hour after hour, without inconvenience. For three years past, all my shoes, even of calf-skin, have been so served; and have, in no instance, admitted water to pass through the leather. It is also a good salve-a basilicon.

Gathering Potatoes.-It has been affirmed that potatoes keep best when gathered damp, with considerable earth adhering to them. It is said that if they are housed when clean and dry; they soon become spongy, and cut, when boiled, like a piece of liver. This, though contrary to the generally received opinion, is certainly worth the experiment.

CHARACTERISTIC ANECDOTE.'

WHEN lord Amherst, on his return from his late embassy to China, mentioned to Bonaparte that the interesting people of the Loo Choo islands, according to captain Hall's account, used neithera rms nor money, Bonaparte broke forth-" No arms! Sacre! how do they carry on war then?" When the same circumstances were related to the chancellor of the exchequer, he exclaimed"No money! bless me! how do they carry on the government?"

THE LONGITUDE.

The following is an extract of a letter from an American gentleman now in England, to Dr. Joel Abbott, of this state, dated 18th May, 1818.

[FROM THE SAVANNAH REPUBLICAN.]

"On my return to this place a few days ago, I learned from some of my American acquaintances, that a new instrument for the discovery of longitude, made by a Mr. Wood, of this place, had excited considerable attention, and some speculation among the savans. Your name was mentioned, and it was said the instrument was made on a theory, or priuciples suggested by you-but in opposition to this, Mr. Wood contended, he had thought of and lectured on the subject twelve or fourteen years ago. I said you had made a short communication of your theory in the Medical Repository, at an anterior period, and on inquiring of a friend of mine in this place, I was fortunate enough to find the volume containing your paper. He was kind enough to lend it to me, and it has been forwarded to Mr. Rush, in London. He, with our countryman, Dr. Henry Jackson, is attending to the subject, and will enforce your claims. There is surely, some mystery in this affair, and this will be the more evident, from the extract with which I shall forward you; although Mr. Wood admits, he had thought of the subject so many years, he says he never made an instrument for testing his theory until he saw Dr. Hall's last year.

"This instruinent (Wood's) I have seen. To the one described by you, it has little resemblance in mechanism, whatever affinity it may have in principle. From a little I have seen of Dr. Hall's, he seems to think he has been infringing on your fair claims; and it appears to me there is piracy some where. It seems most evident there is collusion and fraud some how or other.

"The fact is somewhat singular, that two such important instruments as the quadrant and the one just noticed, should have originated in our country, and the merit of both discoveries are claimed in this. But, my good sir, these are not the only instances of that unwilling spirit on the part of the English to allow the Americans that fair meed of praise to which their genius, talents, and enterprize may entitle them. They would, if they dared, assert, as Monsieur Buffon did of the animals of the new world, that the mind of an American is modelled differently from theirs; and, that it is incapable of attaining the same powers of research or judgment. Facts strangely prove the contrary, and the films of prejudice which covers their mind's-eye, must and will be removed. The people of this country, I find, after a residence of two years, in various parts of it, are jealous of our ri

sing greatness; and the old leaven from which sprang the revolution, and all its blessings, is still fermenting. To this paltry-this mean and petty spirit may be attributed the disinclination in the English to allow any thing excellent, or ingenious, or praise-worthy, to originate with the Americans. In the science of war, the late contest taught them a lesson which they have not forgotten, and however galling to their feelings, they are obliged to admit that the boy had grown a man! To return to the subject which induced me to address you, I am really most anxious to know what would be the result; to whom the honor will attach, if the desideratum should be at last obtained. And if you think I can aid your interests, or forward your views in this country, you may command my services. The following is the extract alluded to, from the European Magazine, for 1802, page 217:

'NAUTICAL DISCOVERY.*

The following is extracted from a letter by a gentleman in Glasgow to his friend in Greenock, dated 2d August.

'An affair of so much consequence to mankind as the following, it were criminal in me to conceal; I therefore request of you to make it as public as possible among your seafaring and philosophical friends. Our mutual friend, before his departure last fall for Philadelphia, constructed a machine, apparently simple, but which is infinitely more valuable to navigators than the compass. It was brought to me, together with his log-book,

*This extract went the rounds of the newspapers in this country in 1803, previous to the publications of Dr. Abbott's ideas on magnetism. But the invention is his; and the probable manner in which they were ushered to the world, through the European Magazine, is thus accounted for. As far back as the year 1795, Dr. Abbott, on a journey from Augusta to New York, fell in, on his way, with a very intelligent and interesting gentleman by the name of -, to whom he communicated with frankness his ideas on magnetism, embracing all the rational thoughts concerning the magnetic ball, or mercury, as described by the "gentleman in Glasgow." Mr. - took unusual interest on the subject, and required reiterated statements of ideas for the sake of distinctness of perception till he seemed to have a clear notion of the doctor's theory of magnetism for defining longitude. It is also true, that on 's arrival at New York he described properties in magnetism, which applied to the discovery of longitudeand spoke of a magnetic ball: and asserted that he had no doubt that longitude would one day or other be much easier kept by magnetism than the latitude is by the quadrant. Now it is not unlikely that Mr.'s public display of Dr. Abbott's theory of magnetism was taken hold of by some ingenious mind, reflected on, and afterwards published in the form we find it in the magazine, than that two persons would hit on the same thoughts at the same time, so much out of the way of common inquiry. Dr. Abbott is now engaged in writing a book on the subject, which, when presented to the world, will have its due weight.