244 TEA DRAWING, A CASE OF ATTRACTION. 



cold or even boiling water, become so at still 

 higher temperatures.* 



It was observed by Lord Bacon, that " we 

 should inquire how far infusions may be made, 

 by the help of attractions." The truth is, that 

 all infusions, like the solutions of salts in water, 

 are obtained by the attractive power of caloric. 

 Cold water has no attraction for tallow, butter, 

 and other oily substances ; but the cook under- 

 stands practically, that when water is raised to 

 a boiling temperature, it will extract and com- 

 bine with the gelatinous and oleaginous ingre- 

 dients of animal bodies, making soups and 

 gravies consequently, that the combining power 

 is not in the water, but results from the agency 

 of heat. 



The chemical power of water is so far exalted 

 by caloric, that, when raised to the temperature 

 400, as in Papin's Digester, it dissolves nearly 

 all animal matters, except the bony phosphate 



* The familiar process of drawing teas depends simply on the 

 attractive power of heat, to which we owe all our infusions, 

 medicinal extracts, emulsions, &c. The superior cleansing 

 property of hot over cold water, is owing to its power of com- 

 bining chemically with the various impurities that adhere to 

 clothing, &c. It is also known that metals are deprived of their 

 drossy combinations, and thus purified by the agency of heat. 

 Hence, among the nations of antiquity, it was regarded as the 

 type of purity a term derived from the Greek word Trvp, signify- 

 ing heat or fire. 



