New York,
July 8th, 1869.

Mr. Editor:—Is it not a most unaccountable fact that the New York Post Office structure, which was to have been commenced some two years since, is as seemingly a myth as one of those “castles in Spain,” of which we all have had at some time of our lives an idea. The site was duly purchased by the United States Government, designs were called for and provided in most eccentric profusion, and the select, if not elect, among the eighth-inch sealed suggestions were liberally paid for in awarded premiums. In fact all that is necessary to trumpet forth an advance was done. Where, then, is the new Post Office? Out of sight—for, even the purchased site itself is not a certainty, then how should we expect to find the Post Office over ground when the ground is not yet decided on.

That Treasury Building at Washington is just now finished, after a lapse of time which makes gray hairs come on in unbidden numbers. Will the infant born this year, behold the promised New York Post Office before his growth of manhood is doubled into

“Lean and slipper’d Pantaloons?”

Alas, the “temporary” addition to that old Dutch church on Nassau street has but too truly proved a prediction, and we of the Empire city will either have to put up with the present arrangement, or build a postal structure of our own. It is evident now that the act of Congress, in this case made and provided, is but

A Dead Letter.

Sarah B.—In the case you mention, the lightning rod was secured to the wall of the house by iron staples. There was nothing to hinder the electric fluid from turning off on one of these, as it actually did. Accidents of a like nature are constantly happening, and where sufficient precaution is not taken it would be far safer to have no conductor.

S. T., asks, is there any bank lock, of how many, and whatever combinations, that is absolutely secure against thoroughly posted and prepared burglars? We doubt that there is. For years the Bank of England trusted its vaults, filled with treasures, to the celebrated Chubb lock. Yet that ingenious Yankee, Hobbs, opened it in a surprising short time. The fact is—what man’s ingenuity can make, man’s ingenuity can also unmake.

C. G., Cincinnati.—We perfectly agree with you; the dwellings of this day are really combustible, and highly dangerous; much more so in fact than before burning fluids came so much into use. We also agree with you that the roofs of houses should not be of a material so liable to take fire on the occasion of a pyrotechnical display, or the passing of a spark-emitting locomotive.

Shingles could be easily rendered fire-proof by steeping them, before use, in a strong solution of alum. But most people would willingly “lose the sheep, to save the pennyworth of tar.”

R. D., Baltimore.—The silica coating of any building material renders it very durable. It is the combination of carbonate of lime, or chalk, with silicate of soda, or what is more commonly known as “soluble glass,” and by the old chemists called “oil of flint,” which, under heavy pressure, produces extraordinary hardness, and causes the great adherence of this cement to iron, brick, stone, or wood. And it is but one more proof of the practical property of the silicate, when applied to purposes such as those in which building most requires its valuable aid.

W. A., Ellsworth, Maine, asks for information as to the best manner of polishing instruments. We would recommend his getting a piece of buckskin and straining it on a square stick, covering one surface with pulverized rotten-stone, or whiting, perfectly free from “grit.” For the instruments in which ink is used, having unscrewed and opened the hinged joints, clean off the ink first with a wet, then with a dry rag. Next rub the blades on the coated side of the buckskin, and lastly on the plain buckskin, until the appearance is satisfactory. We repeat that the pens should not be put away wet, but be carefully dried and rubbed on the buckskin after use. A drop of watchmakers’ oil on the screws and springs occasionally, will tend to insure the long and good service of instruments. Velvet is the best bed for them in the box; and the mould of their tray would be better cut out of cork than of wood. Any one can fit up his own instrument-case to suit his wants. Our advice is to buy only the instruments you have use for, and get the best, keeping them in constant order.

L., New York.—We agree with you, the names of streets should be painted on the lamps, and when a light of glass is broken and replaced the name should also be replaced.

S. R., Reading, Pa.—The idea is not new. Nay, it is as old as the hills. The ancients used hot air flues under their tiled floors. As long as we use boarded flooring we cannot do likewise, for reasons which any insurance office will freely give you.