Improved Apparatus for Sxtlnguisliinjg Fire Wanted. Messrs. Editohs:—I have read with interest your recent article regarding losses by fire from steam heating apparatus. Last winter we had a hot house, the property of Denn s Bowen, Esq., of this city, destroyed by fire. I gave it my opinion that the cause of it was from their heating pipes, which were directly under the wooden platform where the fire first appeared, but those who claim to be competent judges scouted the idea. It seems to me that the sprinkler apparatus used in the woolen mills, alluded to in youi paper, week before last, would be an excellent thing to use in our elevators in this city, which invariably burn up, when they catch fire, owing to the combustible material of which they are made, and the draft caused by the bins running from the top to the bottom of the elevator. I wish you would wake up some of the scientific men to making improvements in the manner and machinery of extinguishing fires, it seems to be the most neglected of all the branches of business. To be sure there has been considerable improvement made, such as the steam fire engines, fire alarm, telegraph, etc., etc. But don't you thhik that there is still further improvement to be made ? It sec-ms to me that a fire engine can be made which does not weigh over three thousand pounds, and still be as effective as the ones which are now used that weigh seven thousand pounds. I have taken great pleasure in reading your valuable paper, and I hope it may long continue in its field of usefulness. Peter C. Doyle. Buffalo, N. Y. Purifying Drinking Water. Messrs. Editors :—Your correspondent in No. 9, present volume, suggests a very good remedy for keeping water pure ; but it is at the cost of extra care, and manual labor, and expense of an air pump which requires close attention to operate successfully for any length of time. My remedy is to use a pump that will give a slight agitation to the water every time the pump is used. I used in a large cistern a Joyce submerged pump, which consists of a semicircular cylinder, with arms extending out each side, and operating on a pivot to force the two plungers back and forth in the cylinder. These arms were connected by rods to a double handle at the top to give motion. This plunger with the two rods produced an agitation that kept the cistern water sweet for years. The pump was located a few inches from the bottom, and it never produced roiling. As the pump was used from twenty to fifty times a day, I think it was more efficient than would be an air pump, with the great liability of neglect. There are similar pumps in use, but I can speak from experience of this one only. Omaha, Nebraska. J. M. Gr. Boiler Test Proposed. Messrs. Editors:—I would suggest through your valuable paper that at the coming exhibition of the American Institute this fall, a test of steam boilers should be made to ascertain what boiler will produce the most steam power with a given consumption of fuel. The proper way to test them would be to have a tank full of water in which a propeller wheel of coarse pitch connected to a 40-horse power -engine is arranged to work. The boiler that gets the greatest number of turns out of the wheel with least consumption of fuel should be pronounced the champion boiler. If a test of this kind takes place, I, for oie, will furnish a 40-horse power boiler of my patent. Hugh Leslie. Jersey City, N. J. [Our correspondent is perfectly safe in this challenge. The American Institute will not commit themselves, we understand, to any test of boilers this year ; but if they would do so, they would scarcely permit so unscientific and unsatisfactory a method as our correspondent proposes. We have asserted and reasserted over and over again that the only reliable test of a boiler is its evaporative power compared with the fuel it consumes, and yet our readers will persist in complicating the problem by saddling some other condition upon it. As well might it be proposed to test a boiler by running an engine and a cotton mill with it as an engine and propeller wheel. Believe us, friends, an engine and boiler ve two distinct animals. They don't belong even to the same genus, let alone species. To test the speed of a horse we do not tie ai; elephant to his tail and rr|.n the two togetlier.—Eds. As far as man can go back in time, says Dumas, as far as man cm reach by observation in space, the concrete elements of matter present th same character m Jjavoisier's de-