Chemical Philosophy. 103 



land Industry, must undoubtedly be given to their 

 author/ 



Besides the revolutions and improvements in 

 the doctrines and in the language of chemistry 

 which have been detailed, various instruments and 

 machines, of great value, for measuring chemical 

 substances, or facilitating chemical processes, have 

 been invented in the course of the last century. 

 Of some of the most important of these it will 

 be proper to give a short account. 



At an early period of the century, while spe- 

 culations on the nature and properties of Heat en- 

 gaged the attention of the philosophical world, 

 various contrivances for measuring this fluid were 

 invented and adopted. The Thermometer, which 

 had been first used about the beginning of the 

 preceding century, was constructed on a new and 

 improved plan, by Sir Isaac Newton, in 1701. 

 He chose, as fixed points of graduation, those 

 at which water freezes and boils; a choice which 

 the experiments of succeeding philosophers have 

 proved to be the most wise and convenient. He 

 also introduced the use of oil to fill the tube, in- 

 •stead of alcoliol, under an idea that the former 

 was liable to fewer disadvantages than the latter. 

 But, after all the labours of Sir Isaac, this im- 

 portant instrument was imperfect, and could by 

 no means be considered as an exact standard for 

 pointing out the various degrees of temperature. 

 Accordingly, about the year 1724, Mr. Fahren- 

 heit, of Amsterdam, suggested the use of ther- 

 mometers made with mercury, and presented one 



i Those who wish to see a more detailed account of Dr. Mitchill*5 

 new chemical opinions and terms, will find it in his Explanation of the Sy 

 nopsis of Chemical Nomenclature and Arrangement^ See. lately published. Much 

 information on this subject may also be found in the volumes of the Medical 

 Repository^ and in several of the European journals. In these publications 

 the reader will see the respectful manner in which the inquiries of the 

 learned Prof^s^pr have been noticed in different part* of £wope. 



