14 AGRICULTURAL CHEMISTRY. 



salt ; and mucb more of some other salts. Several 

 substances are more soluble in cold water than in hot. 

 .Glauber's salt, for instance, is dissolved to a greater 

 extent in cold, than in hot water. Common salt has 

 the property of being equally soluble in cold water 

 and in hot. If you put into 11 pounds of cold water 

 4 pounds of common salt, it will all be dissolved. K 

 3^ou put in more, all beyond 4 pounds will fall to the 

 bottom undissolved. Precisely the same will take 

 place if the Water be hot. In either case the water 

 will hold in solution 4 lbs. of the salt to 11 of its own 

 weight. Most substances, as is well known, are dis- 

 solved more readily, and in larger amounts, in hot 

 water than in cold. 



11. It is a general law of chemical combination, that 

 elements will combine with elements only, and compounds 

 only ivith compounds. According to this law, a body 

 that is constituted of one kind of matter only, will com- 

 bine with another body similarly constituted, but not 

 with one that is composed of two kinds ; and a body, 

 composed of two kinds of matter, will combine with 

 another that is constituted similarly, but not with one 

 that contains but one kind of matter. 



12. All chemical combinations are in certain^ definite 

 proportions. Bodies will not combine in any propor- 

 tions which the chemist might prefer, but only in cer- 

 tain proportions, fixed in nature, and unalterable. In 

 illustration of these principles, it may be stated that 8 

 lbs. of oxygen, an element^ will combine with 1 lb. of 

 hydrogen, another element, and form 9 lbs. of water.. 



