638 Transactions of the American Institute. 



guard against the baneful effects of nicotine, by placing in the 

 tobacco-pipe a bit of cotton impregnated with tannic and citric 

 acids, which will arrest the alkaloid and form tanuate and citrate 

 of nicotine. 



\\'ELDmG IRON. 



M. Lietar, of Brussels, has described a new method of welding 

 iron or steel, or iron with steel. He calcines and reduces to a fine 

 powder, one kilogramme of iron or steel filings, one hundred 

 grammes of ammoniac, sixty grammes of borax, and fifty grammes 

 of balsam of copaiva. One of the pieces of iron or steel to be 

 soldered, is brought to a red heat, and, after being cleaned with a 

 wire brush, the powder is spread upon it, and the other piece of 

 metal, at a white heat, is brought in contact with it; thus a perfect 

 welding is effected. 



A GREAT BALLOON. 



At the Paris Exposition a balloon, in the form of a perfect 

 sphere, and about two hundred and ten feet in circumference, is 

 held by a cable, and makes hourly trips upward, in the same 

 manner as worked in a model at the last exhibition by the American 

 Institute, and as operated on a large scale at the New York Central 

 Park. The balloon is to be filled with hydrogen, the most buoyant 

 of the gases, which will be made by decomposing steam by means 

 of red-hot charcoal. By this process, it is said hydrogen gas can 

 be furnished at about two dollars and seventy-five cents per one 

 thousand cubic feet. 



INCREASING THE SUPPLY OF WELLS. 



Mr. Donnet, a civil engineer of Lyons, France, has patented a 

 method of increasing the quantity of water in wells which cannot 

 be easily made deeper. It is simply to cover the top of a well 

 air-tight, and to exhaust the air by a pump, thus making the atmos- 

 pheric pressure assist the water in its percolations. The height 

 of the water in the well, within thirty-three feet, will depend on 

 the relative vacuum obtained. Another pump, inserted through 

 the covering and reaching the water, will draw it in the usual way. 

 It is not claimed that there is any saving of power by this mode^' 

 of operation. 



DRAWINGS ON POLISHED AGATE. 



The curious figures sometimes found on agate may be imitated 

 by drawing the design with a common goose-quill, wetted with a 

 strong solution of nitrate of silver, and exposing it to sunlight. At 



