Chap. I. APPENDIX. 319 



To thefe authorities, I would have the ftudcnts of chymlftry, a 

 ftudy very much in falhion at prefeiit both in England and France, 

 add the authority of their mailers in that art, Van Helmont and 

 Paracelfus, the firfl: experimental philofophers in Europe, who have 

 mauitained the very fame dodtrine that I maintain concerning the 

 origin and continuation of Motion *. 



By any thing I have faid here, on the fubjed of the Newtonian 

 aftronomy, I would not have it underftood that I mean to difparage 

 the fcience of mathematics. I have faid elfewhere, and I repeat it 

 here, that I hold the mathematical fcience to be not only very ufe- 

 ful in the arts of life, but alfo in philofophy, if it be ufed as the 

 handmaid^ not as the mijlrefs. But, undoubtedly, very improper 

 ufes have been made of it, fuch as thofe ridiculed by Swift, in his 

 voyage to Laputa ; and it has really been applied to fome other, not 

 much lefs ridiculous. About the beginning of this century, phyfic 

 had become mathematical, and the laws of mechanifm were applied 

 to the animal oeconomy, and difeafes in that way accounted for. A 

 more extraordinary application dill of mathematics was made by 

 Mr Hutchifon of Glafgow to the moral fcience, and the degrees of 

 virtue and vice we were taught to calculate by algebra. In order, 

 therefore, to make a right ufe of his art, every mathematician 

 Ihould know what the fubjed of it is, which is no other than Quan- 

 tity. If he is fo ignorant of the elements of pliilolbphy, as not to 

 know what quantity is, I mufi refer him to what I have faid in the 

 Flrft and Second Volumes on that fubjed, where he will find it de- 

 fined and divided into quantity difci^ete and quantity continuous'\ , The 

 flrft is the fubjed of arithmetic^ the fecond oi geometry^ which exa- 

 mines 



* See what I have faid upon this fubjeft, Vol. i. p. 239. 

 f Ibid. p. 439. ; Vol. ii. p. 22. 



