1004 Transactions of the American Institute. 



April 23, 1868. 



Prof. S. D. Tillman in the chair. 



The meeting was opened by the presentation from the chair of 

 the following notes on new discoveries and inventions : 



IMPROVEMENT IN MAKING GLASS. 



The changes of various kinds which glass undergoes have recently 

 been subjects of considerable discussion. Some varieties of glass 

 cannot be perfectly cleaned, owing to its hygroscopic nature and 

 the tendency of this silicious compound to decomposition. The 

 pure white unalterable Bohemian glass is a silicate of lime and 

 potash, but it is very infusible and difficult to work. Taking advan- 

 tasre of the well-known fact that a mixtm-e of the cai'bonates of 

 potash and soda fuses at a lower temperature than either salt alone, 

 Prof. Stas substitutes such a mixture for the potash, and thereby 

 obtains a glass as unalterable as the Bohemian variety, but much 

 more fusible. 



COLORED INKS. 



Fuchs's method of makuior colored inks is to dig-est for three 

 hours a quarter of an ounce of aniline, of the color desired, with 

 two ounces and a half of alcohol; then to add a pint and a half of 

 water, and heat the whole gently until all the alcohol is driven off, 

 after which one ounce of gum arable dissolved in eight ounces 

 of water is added. The solution is allowed to stand until the 

 impurities have settled, and it is then ready for use. 



VALUABLE CEMENT. 



Dr. ToUens mixes equal weights of oxyd of zinc (commercial 

 zinc white) and very fine sand, to which is added a solution of 

 chloride of zinc, having a density of 1.26. The paste thus formed 

 sets rapidly and resists the action of most acids. American dentists 

 have employed for many years the same paste, substituting pow- 

 dered quartz for sand. This paste, however, does not resist the 

 action of the saliva of the mouth for any great length of time. 



ORNAMENTED PAFER. 



Puscher's process for ornamenting paper with silky crystals is 

 to mix the gum made by heating commercial starch to 320 degrees 

 Fahrenheit, known as British gum, with equal parts of Epsom salts 

 and of water, to which is added a small quantity of glycerine. 

 After being brought to the boiling state the mixture is immediately 



