Milk for Lubricating Wool.—Before wool can be carded, spun, and woven, it is well greased with a suitable unctuous substance. Various matters have been employed as substitutes for oil, because the item for such an expense in a year in any large factory, is very large. A few years ago, a patent was taken out for the employment of steam as a substitute for it, but we believe, it has not answered the purpose. By a late English paper, we learn that the price of olive oil, the substance used for wool in the manufacturing districts, had arisen so high ($200 per ton) that many experiments were made to get a suitable substitute, and that sweet milk was discovered to answer every purpose, when mixed along with a small quantity of olive oil ; it is even asserted that it answers better than olive oil alone. Practice is the only way to test the value of any such discovery ; we know that pure olive oil and soda, dissolved in water, make a composition which looks, tastes, and smells very like sweet milk. It is extensively used in dyeing and softening colored goods, and for dressing black silk. The milk cannot be such a good substance as olive oil— in our opinion—for treating wool, but its greater cheapness will enable manufacturers to use it in greater quantities. NEW QUARTZ CRUSHING MACHINE—The London Illustrated News thus speaks of a rather singular machine for crushing quartz : It consists of an iron chamber with safety valves on its upper part. A mortar is charged with powder and filled with quartz and is discharged into the chamber by one of the val ves. The quartz is reduced to powder, and a bellows makes the powder of the silex fly out at one part, while the gold dust, by its specific gravity, like as in some of our grain separating machines, drops down into another chamber. This as described by the News, is certainly the most novel and powerful means of quartz crushing and separating that has yet been brought before the world. We are inclined to the opinion that the process is an exceedingly dangerous and explosive one. PHILLIPS SUBMARINE PROPELLER—Mr. L. D. Phillips, whose submarine propeller was illustrated on page 172, writes us, stating that he can raise and submerge his vessel rapidly simply by filling up the water cylinder with water, and he can again rise to the surface as quickly by forcing out the water through a tube in the bottom by means of the air acting upon the surface of the water, it being forced in by the air-pump. In case the force of the air is not enough, the water can be let into the cabin, and forced out with a force pump ; or without discharging ballast, the action of the paddles will force the vessel up to the surface. This propeller can also be made to stand at any depth of water. NEWEI.LS WIRE GAUZE LAMP—-We have received a letter from Prof. J. R. Nichols, of Haverhill, Mass., to correct an opinion, which has gone abroad respecting Prof Silliman having committed himself in favor of Newells device of wire gauze in fluid lamps. Prof. Nichols says he has received a letter from that distinguished gentleman, in which he says : in my remarks respecting safety lamps, I say if they are faithfully constructed, they are safe, and I have made no allusion to Mr. Newell as an inventor or any other person, as it regards claims or skill. If I understand you correctly, you believe in the sufficiency of wire gauze protectors, if properly constructed and applied, and my opinion endorses nothing more. Prof. Nichols says,—justice to Prof, Silliman and to the public will doubtless lead you to correct an erroneous impression, which places a distinguished and excellent gentleman in an unpleasant position. We always aim to get the truth—the whole truth, and nothing but the truth—to present to our readers. We are therefore always happy to present any statement in correction of an error, or to remove any wrong impression from the public mind. The letter of Prof. Silliman dated Jan. 29th ult., and which was published in the Boston Traveller, would lead any person to infer that he had committed himself in favor of the said lamp. It concludes with these words, The danger (explosions) may be entirely avoided by the use of Wire Gauze Protectors that have been recently introduced. It may be proper to add that I have no interest whatever in the invention. PUBLIC VIRTUE IN PUBLIC MEN—Alas for our country at the present day, it has a most unenvious name for corruption in our public men. The Common Council of the City of New York stands at the present moment blackened and stained with more corruptible characters than any corporation of the rotten-est Rotten Borough of Old England. The common impression on the public mind is, that the majority of public men have their price, and that many know exactly what that price is. The late Grand Jury of the City and County of New York, indicted two of the New York Aldermen for receiving money illegally, and it was perhaps owing to the refusal ot witnesses to testify, that no more were included in the verdict. The whole ot our Aldermen have also been found guilty of contempt, of a decree of the Superior Court, and they stand before the public in a very degraded light. Never in the whole history of our country has such a city been so disgraced by the acts of its corporate authorities. A reform of our City Charter is demanded, and large meetings have been held by our citizens to accomplish that object ; but neither new charters nor penal laws can make corrupt men virtuous. Good men will enact good laws, and execute them faithfully ; corrupt men will violate good laws, or make bad ones for their own purposes. Our respectable citizens —the moral, intelligent and influential among all classes, rich and poor, are to blame for not doing their duty, in placing men of good character in power. The taxes in the City of New York, are higher than those in London or any city in the world, and yet no city is worse governed. A reform is certainly demanded, but it must be a moral one, to do any good.