The Editors are not responsible tor the Opinions expressed by their Correspondents. Grindstones.—Where they come from, and How they are Made, MESSES. EDITORS :—The sandstone formation overlying the coal beds of England furnishes the grindstones of that country, the principal quarries being located at Newcastle-upon-Tyne, and at Wickersley, near Sheffield. These quarries are worked by hand, and all the grindstones are made with mallet and chisel, and have been imported into this country for over one hundred years. The grindstones from the provinces of Nova Scotia and New Brunswick, are also the over-lying sandstone formations of tlie coal districts bordering on the Bay of Fundy, and extending across the Province to the Gulf of St. Lawrence. These immense deposits contain a great variety of grits, known as the Nova Scotia grindstones. These quarries are generally worked by the French people known as " Acadians," from the name they gave this country, "Acadia," and are the descendants of the " Huguenots," who were driven out of France by religious persecution. They are a very industrious and simple-minded people, and the females retain to this day the style of dress brought over from France by their ancestors. The tides of the Bay of Fundy rise and fall from 60 to 70 feet every twelve hours, and these people avail themselves of this-power to work the quarries, which extend from a high bluff on the mainland, down to low water mark in the bay. At low water a huge mass of stone is loosened from its bed and a heavy chain is passed under it and over a large boat, which is placed alongside. As the tide rises, the stone, attached to the bottom of the boat is floated into a sand cove at high water, and made into grindstones after the tide recedes. This work is done with mallet and chisel, the rough parts being first chopped off with a heavy ax. Machinery has been recently introduced, and the small grindstones are now turned in a lathe by steam power. The sandstone deposits of this country which are made into grindstones, are found along the shores of Lake Erie, and extending for a considerable distance east and west of Cleveland, and inland as far as Marietta, on the Ohio. They are also found on the shores of Lake Huron, above Detroit. These deposits are of a different character from the foreign stone, and do not seem to be the overlying strata of coal formations, but appear to be a later formation, as the quarries look as though this part of Ohio had once been the bottom of the Lake, the sand of which had become solid, and been up-heaved by some convulsion of nature. Nearly all the Ohio grindstones are made by machinery driven by steam power. The blocks of stone being loosened from the quarry bed, are roughly hewed out, with a square hole in the center. This is placed on a heavy square iron shaft furnished with a 9-inch collar, against which the stone is securely fastened by means of another collar keyed against the side of the stone. The shaft and stone being driven by steam power, two men on opposite sides of the stone turn it off perfectly true, by means of soft iron bars about 6 feet long, and 3 by J-inch thick, which are drawn out to a thin point, which is curved upward. This was formerly a very unhealthy occupation owing to the shaft dust being inhaled by the workmen, but this difficulty is now obviated by means of blowers which drives it away. J. E, MITCHELL. Philadelphia, Pa. Defense of Patent Right Dealers, MESSES. EDITOES :—I notice in several late newspapers that a professor in an agricultural institution of this State, who evidently sets no common value on his own sagacity, warns farmers of the dangerous character of " patent-right men," advising them in no case to have anything to do with the men, or their goods, affirming that in ninety-nine cases out of a hundred these men are robbers, and that their machines are altogether worthless, etc., etc. Now admitting that some of these inventions are of no value, and that persons engaged in selling them have, in some instances, taken undue advantage of the inexperience, credulity, or ignorance of the parties with whom they have dealt, it appears to us to be making rather wholesale work of it to condemn all new inventions indiscriminately at "one fell swoop"—together with the persons engaged in introducing them. We think that not many farmers will see proper to follow the professor's advice, so gratuitously offered. It should be regarded as only an insult offered to their understanding. Farmers, as a class, are sensible men, why not let them examine new machines, and decide for themselves ? The professor's method seems to us to do great injustice to inventors, as well as dealers in patents. It may be asserted that no class of men are more indebted to inventors than farmers. They can now, with their improved machinery and implements, accomplish more in a day than they formerly could in a week. Much of the work then performed by human muscle exclusively, is done in one tenth part the time, and less than half the expense, by steam or horse-power. Now, for farmers to " go back " on the men by whom they have received most benefit, would be as unwise as it would be unjust. Intelligent farmers who study the best books on farming, and who are regular readers of such excellent journals as the American Agriculturist and SCIENTIFIC AMERICAN, are in v ery little danger of being " fobbed " by " patent-right men." JOSEPH R. PARKS; Muscatine, Iowa. Ripening of Wine—America Ahead of France. MESSES. EDITORS :—Your number of July 31, page 68, states the effects on the wine by the method of heating called Pasteur's process. Permit me to explain the cause of the i effects aforesaid, so that your readers may intelligently j udge of the merits of the heating process. All fermentation results from the presence of certain microscopic fungi, shortlived, but multiplying with astonishing rapidity under favor- ! able conditions of temperature and atmospheric oxygen in liquids, that contain nitrogenous parts; on these glutinous albuminous parts they feed, and on them their existence de-pends,the want of gluten precludes their existence. While their action in maturity is to convert the sugar of the fluid into alcohol, a certain high proportion of alcohol terminates their existence, as well as a very large excess of sugar extinguishes their function; fermentation ceases. But this species flourishes only when supplied with atmospheric oxygen. This wanting, they barely exist but in the state of spores or seeds, ready to take maturity and propagate by obtaining the proper conditions to their support. Still, while the species of myco-derms, that causes beneficial or purely alcoholic fermentation, finds insufficient atmospheric oxygen in the fluid for their support, other kinds, able to do with less or differently composed air, can obtain a foothold—provided always there is gluten—and by their presence cause putrefaction decay, diseases, or under certain conditions of continued surface contact with atmospheric oxygen acetic acidification. Now, all this organism, and the spores or seeds from which they originate, are killed in a brief time at a temperature exceeding about 135 F., or slowly die if 121 to 135 F., is proportionally longer continued. The principal part of the foregoing has been satisfactorily established by the laborious investigations of Mr. Pasteur, who fully deserves all praise allotted to him. His works, however, do not show that he paid particular attention to the gluten in liquids to be preserved by heating, but we learn that the spores or organism floating in the air, may subsequently contaminate the wine, which will be restored again and again by heating—still, gluten remains. This is very well, but as the organism cannot live without gluten, is it not so much more perfect a cure to extract at once the gluten, the sustenance of the mycoderms, the root of all disease ? A penny's worth of prevention is better than a dollar's worth of cure. Air-treatment, while it promotes, accelerates, and controls all fermentation, eliminates from all fermenting (and other) fluids the gluten by oxidation, which renders it insoluble, and therein lies a total and economical prevention from all further injury by destructive mycoderms; and without the expensive, and to the common producer of fermented beverages, impracticable and impossible arrangements for carefully heating wine, cider, beer, etc. Thus America is ahead of France. P. 0. Box 6,844, New York city. R. D'HEUREUSE. Novel Mode of Obtaining Capital, MESSES. EDITOES.—I have been unfortunate in business and am anxious to make another start. I propose insuring my life in favor of any one in a mutual life insurance company for $20,000 the party paying the premium receiving the dividends and who will give me $12,000. I will insure in any company the party may wish, and take out any kind of policy. I will pay the premium the first year. If you will exert yourself and make. this arrangement for me, I will come on as soon as I receive a notification from you, and as soon as I receive the money will pay you $1,000. It appears to me that almost any of the large capitalists in New York who desire to invest their money in something safe, would make this arrangement, as it would be perfectly safe, at the same time paying a dividend annually. Let me know from you what you think of the proposition and whether you think it practicable or not. I am only 24 years of age, therefore the premium would be very trifling. A. C. MCRAE. Macon Depot, Ala. [We unfortunately do not know of any capitalist likely to take a venture in the manner our correspondent suggests. If this should meet the eye of any person having $12,000 to thus invest, he may correspond and remit as above. The thousand dollars promised us, may be sent direct to this office.—EDS. Explanation of Singular Phenomena. MESSRS. EDITORS :—In answer to your inquiry in the present volume, page 70, for an explanation of the curious phenomena noticed in an oil jar, I think I can give one. When the jar is placed upon a painted board or a hard pine board, the oil exuding from the jar forms with the paint or the pitch in the hard pine board, a gum which prevents further leaking. On the contrary, black walnut being a dry wood the oil cannot form a gum, and consequently it escapes. Sunbury, Pa. E. H. SCHNEIDER. Another. MESSES. EDITOES :—In answer to your inquiry in number of July 31st, under article headed " Curious Phenomena," may not the reason for the oil exuding from the jar when placed upon a black walnut bench, be on account of the openness of the fibers producing capillary attraction, which would not be the case with a painted board, the paint filling the pores on the surface and destroying this attraction; and the same result would be produced by substituting- the hard pine board, as the pitch closes the pores the same as the paint on the painted boards ? If your correspondent would place the jar upon a piece of ash or chestnut board with the same result as upon the painted board, I should think the theory of capillary attraction might be erroneouSi A. T A. Lowell, Mass, A Remedy for Lockjaw. MESSES. EDITOES :—I am extremely sorry to learn of the death of my old friend, Mr. John A. Roebling. If I had known in time that he had lockjaw I could have saved his life, and would willingly have traveled many miles to do it. Let any one who has an attack of lockjaw take a small quantity of spirits of turpentine, warm it, and pour it on the wound—no matter where the wound is, or what its nature is —and relief will follow in less than one minute. Nothing better can be applied to a severe cut or bruise than cold turpentine, it will give certain relief almost instantly. Turpen. tine is also a sovereign remedy for croup. Saturate a piece of flannel with it, and place the flannel on the throat and chest—and in very severe cases three to five drops on a lump of sugar may be taken inwardly. Every family should have a bottle of turpentine on hand. D. A. MORRIS. New York city. [We would not be understood as indorsing the above remedy, because we have not tried it. It is a simple matter, and can be easily tested. In all serious ceses the application should be made under medical advice.—EDS.