392 Intelligence and Miscellanies. 



liquid can furnish. The chloride of lime is reduced to near- 

 ly _^_ by ebuHition. Thus during its fabrication, heat may 

 destroy one third of its power of discoloration, and when dis- 

 solved, ebullition destroys the other two thirds. — Ann. de 

 Chimie et de Phys. Fev. 1828. 



24. Ultra-marine. — Gay Lussac announced to the French 

 Academy on the 4th of February, that M. Guimet, his ad- 

 junct in the saltpetre and powder works, had succeeded in 

 making ultra-marine of all varieties by combining the prin- 

 ciples which by chemical analysis are found to exist in it. 

 This new product has a richer and more splendid color than 

 the natural lapis. — Idem. 



25. Heat of combustion. — M. C. Despretz has discovered, 

 by employing an improved calorimeter, that for every grain 

 of oxygen absorbed, hydrogen disengages 2578 of heat. 



Carbon 2967 



Iron 5325 



Phosphorus, zinc, and tin disengage quantities about equal 

 to that of iron. 



Hence, of all bodies, hydrogen is that which developes the 

 least heat in absorbing the same quantity of oxygen gas.* 

 The metals are those which disengage the most. 



It is remarkable that carbon, which does not change the 

 volume of oxygen gas, sets free a quantity of heat equal to 

 three fifths of that which is liberated by iron and other metals. 

 —Ibid._ 



26. Force of chemical action. — M. Babinet discovers that 

 at the temperature of 77° F. the force with which hydrogen 

 is disengaged from water, zinc and sulphuric acid, surpasses 

 the pressure of 33 atmospheres. 



At the temperature of 50° F. the action stops at a pres- 

 sure of 1 3 atmospheres. 



At common temperatures, chlorine disengaged by hydro- 

 chloric acid and oxide of manganese has an elasticity of 

 about 2 atmospheres only. — Ibid. 



27. Evaporation by means of bladders. — M. Saemmering, 

 in a memoir in the Academy of Sciences of Munich, states 

 that alcohol, in a vessel covered with bladder, the latter not 

 being in contact with the fluid, loses, when exposed to a dry 



* How can this be true when the compound, or oxy-liydrogen blowpipe pro- 

 •luces a degree of heat, so much superior to that evolved by a stream of oxygen 

 gas directed upon ignited charcoal or metals ? — Ed. 



