COOEING OF ANIMALS EXPOSED TO GREAT HEAT. 36\ 



the sulphate of soda, and thus remoTes the obstacle, that 

 prevents tho soda from acting on ti.e silex. The best me- 

 dium that can be employed is charcoal, or for fiiut glass 

 metallic lead. 



This decomposition may be conducted during the vitrifi-I'>ecautlonsne- 

 cation, or previous to it. The methods employed must be*^^^^^"^^' 

 Taried according to circumstances, but it is essential to ob- 

 serve, 1st, the property charcoal has of colouring glass, 

 even when in very small quantity ; this property of char- 

 coal not being exceeded by any of the metallic oxides 

 hitherto known: 2dly, the preference to be given to lirac 

 reduced to powder, dissolved in water, and heated anew, 

 before lime slacked in the air: 3dly, the great eU'es vescence 

 of the glass, when sulphate of soda is employed, an effer- 

 Tescencc, however, not greater, than sometimes arises from 

 common soda ; and hence the precaution that must be taken 

 to add it in smaller successive portions, than if potash 

 were employed : 4th!y, that the work must be carefully 

 distributed in glasshouses of this kind, not to be troubled 

 by this eflPervescence: 5thly, that snlphuret of soda may- 

 be more useful in glassmaking than sulphate of soda : and 

 lastly, care must be taken in preparing the pots, because 

 the sulphate of soda has a particular eifect, as every other 

 flux has. 



VI. 



On the Cause of the Refrigeration observed in Animals 

 exposed to a high Degree of Heat: by P'rancis De- 

 LAROCIIE, M. D. *. 



i. HE animal economy presents us with phenomena, which. The animal 

 diifering in their nature from those exhibited by inorganic ?g°"°™^^"JJ^ 

 bodies, cannot be explained by the ordinary results of the as well as phy- 

 laws of physics ; while at the same time it produces others, ^'^^ ^^^" 

 which, being more or less similar to physical effects, are 

 apparently derived from the same laws. Some physiologists, 



* Journal de Physique, vol. Ixxi, p. 289. Read to the Institute 

 the 6th of November, 1809. 



