NOVEMBER 16, 1889.] J titufifit �tutritJu. (1504) B. S. asks the power of a 10X12 engine, 2)4 inch feed pipe, with 70 pounds pressure. A. The power of your engine depends upon the speed, us well as the figures given. At 150 revolutions per minute it will have about 45 horse power. The cut-off has also much to do with a computation of it.s power. 'rhe mean pressure upon the piston as governed hy the cut-off, multiplied by the area of the piston in square mches, and this product multiplied by the

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... speed of the piston in feet per minute. and t.he last pro duct divided by 33,000, gives the answer in indicated horse power. {1505) F. A. M.-There is no reliable Cure for warts. They generally leave of their own ac cord after a time. We have no special work on brass finishing. For brass coloring, bronzing� and lacquering, "The Techno·Chemical Receipt Book" contains valu able receipts and processes in all departments of indus try. Price $2 mailed. "The Mechanic's Friend" is also a good book on general mechanical work, $1.50 mailed. You can make a good dip for brass by mixing equal pmts strong nitric and eulphuric acids. Have the work perfectly clean by alkali wash. dip for a moment, and wash in clean hot water. Dry hot. and lacquer. (1506) H. A. writes: 1 I have a yellow prune plum tree, and the frnit when half grown bleeds and forms a gum, the fruit then falling off. What causes this? A. 'I'he bleeding is probably caused by the sting of an insect. 2. Can you give me a receipt for making a good and cheap ebony stainer to use on poplar wood-something that will not rub off when varnish· ing? A. Boil 40 parts gall nuts. 4 parts logwood chips, 5 parts each sulphate iron and verdigris. Strain, and apply to wood. Then apply a coat of a solution of one part iron filings diswlved in 7 parts vinegar. (1507) <:t. B. C.-The maximum safe ve locity of cast iron fiy wheels should not exceed a rim speed of 80feetper second.