396 Foreign Literature and Science. 



of this salt was so abundant, that several pieces detached 

 from the walls of the house weighed near a kilogramme, 

 2ilb. With proper attention, the collection of it might certain- 

 ly be rendered lucrative. Whence proceeds the hydro-chlo- 

 ric acid of this ammoniacal salt? This question it does not 

 seem easy to resolve ; but one thing is certain, all the water 

 of the coal pits of St. Etienne contains among other salts a 

 notable quantity of hydro-chlorates with earthy bases. 



38. Vaporisation of Ether. — Cagniard de la Tour has 

 shewn by experiment that Ether is susceptible of being re- 

 duced to vapour in a space less than double its primitive 

 volume, and alcohol in less than three times its volume. 

 In these cases the former exerts a pressure equal to 37 

 or 38 atmospheres, and the latter, a pressure equal to 119 

 atmospheres. To effect such a vaporisation ether must be 

 heated to 320° F. and alcohol to 405° F. 



39. Paper Hangings. — To guard against the effect of 

 dampness in the injury and destruction of paper hangings, a 

 method has been adopted in London which proves to be 

 very effectual. Very thin sheets of Lead are fastened to 

 the walls by copper tacks, and to this the paper is pasted 

 without any difficulty. The lead is as thin as the sheet used 

 in the lining of tea boxes, and effectually excludes the mois- 

 ture of the wall. 



40. B rich-making. — A patent or privilege has been ob- 

 tained at St. Petersburg for a press for making bricks, which 

 is not only to diminish the labor, but to perfect the forms of 

 the bricks. By means of this machine, not only bricks, 

 both solid and hollow can be made, but tubes straight or 

 crooked, cornices, flutes for columns and other architec- 

 tural ornaments. The patentee is a M. Chomas who pro- 

 poses to establish a model brickyard with improved ovens 

 for baking the bricks. Three or four men can produce, it 

 is said, with this machine from 10 to 12 thousand bricks, 

 daily, of different forms. 



41. Leipsic. — The number of students attached to the 

 University of Leipsic, during the last winter session was 

 1102, of whom 480 applied themselves particularly to the- 



