Proceedings of the Polytechnic Association. 943 



Photograj^iis in Tombstones. 

 The English correspondent of the Paris Moniteur, in noticing the 

 fact that photographs of deceased persons are now often inclosed in 

 their tombstones or vaults, adds that when vitrified photographs are 

 more attainable, the use and availability of this practice will be more 

 •apparent. 



Kkw Material fob Bricks. 



Ashes and cinders, under the name of breeze, have been employed 

 as components of certain kinds of London bricks, but Dr. Wagner 

 now proposes to make bricks almost entirely of ashes and coke. His 

 process consists in mixing ashes with coke broken into small pieces, 

 and afterward adding ten per cent in weight of slaked lime, with 

 sufficient water to make the mass plastic, which in a day or two will 

 have the proper consistency. The bricks are moulded under con- 

 siderable pressure and then placed in the open air to dry. In about 

 fourteen days they are ready for use. It is claimed that such bricks 

 are useful in making light dry walls. 



The Preservation of Eggs. 



The plan extensively employed in Paris is to place the eggs in wire 

 baskets, each holding about a dozen eggs, and plunge them into 

 cauldrons of boiling water, where they remain for about one minute. 

 Thus a thin layer of egg coagulates on the inner surface of the shell, 

 and prevents that passage of the oxygen of the air inward which is 

 fatal to its freshness. 



l!^EW Use of Glycerine. 



When constant temperatures above the boiling point of water are 

 required, M. Yogel recommends the use of glycerine in place of the 

 oil bath. Glycerine of 1.25 density boils at 128 deg. Centigrade, or 

 at between 262 deg. and 263 deg. on the Fahrenheit scale. A mix- 

 ture of glycerine and water in equal parts boils at 102 deg. C, or 

 between 215 deg. and 216 deg. F. ; three parts of glycerine with 

 two of water boils at 106 deg. C, or 222.8 deg. F. ; seven parts of 

 glycerine with four parts of water boils at 109 deg. C, or 222.2 

 deg. F. 



Dr. L. Feuchtwanger exhibited specimens of apatite, and then read 

 the following paper : 



