918 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



American Institute Polytechnic Association, 



April 11, 1867. 



Prof. S. D. Tillman in the Chair; T. D. Stetson, Esq., Sec'y. 

 The Chairman presented the following notes on recent progress 

 in science and art. 



Magnesium Alloys. 



Mr. Parkinson of the London School of Mines, found most of 

 such alloys made by him very brittle and easily acted on by air. 



To Detect Woody Fiber in Paper. 



The paper is touched with ordinary strong nitric acid {thalanit). 

 if wood fiber is present the paper will be colored bro^\Ti, espe- 

 cially on warming. This reaction is more delicate than that with 

 sulphate of aniline. 



An Ink for Glass. 



M. Kessler, of France, has, by means of fluor-hydrate of ammo- 

 nia (olanaf), and hydro-chloric acid {thalad), properly thickened, 

 made an ink, by which, with any pen, ineffaceable characters can 

 be traced on glass. This ink will be of service to the chemist and 

 apothecary in labeling bottles, and marking graduations on glass. 



Aluminum Leaf. 



M. Degousse, a gold-beater in Paris, has prepared aluminium 

 leaf weighing only .01544" of a grain per square inch, which 

 burned with great brilliancy in the flame of a spirit lamp. In 

 this form the affinity of aluminium for oxygen is said to be strong 

 enough to decompose boiling water. 



The Atlantic C^vble. 



This submarine cable is said to be often worked with great diffi- 

 culty from daylight until two o'clock in the afternoon, after which 

 the working grows easier and more rapid until dark. Through 

 the night it is in the best condition. The same phenomena have 

 been noticed on some land lines. 



Bleaching Powders. 



Mr. BoUey has found that hypochlorite of magnesia {7nagmedet) 



bleaches much more rapidly than hypochlorite of lime (calcmedet), 



especially in the case of straw, for the latter compound first colors 



the straw brown, and then bleaches very slowly. The cause for 



