464 PHILOSOPHICAL TRANSACTIONS. [aNNO 1720. 



parts of any simple, or rather suspend its more solid particles, is to use the hy- 

 drostatical balance ; when weighing the menstruum before infusion, and after 

 the matter has been infused for some time, it will soon be observed by the 

 augmentation of the weight, how far the menstruum is impregnated, and which 

 is the most proper dissolvent. The proper method of exhibiting the fixed 

 simples, if not in substance, is by decoction, infusion, or tincture. (N. B. It 

 is called infusion, when the menstruum is either water, ale, or wine; but a 

 tincture, when brandy is employed.) And the best way to obtain the useful 

 particles of volatile, tenuious, or subtile substances, is by distillation. These 

 may indeed be proper ingredients for an infusion or tincture. But there are a 

 great many fixed substances as improper for distillation, as the volatile are im- 

 proper for extracts. Thus I have shown the means of finding out the virtues of 

 plants, without dissolving their texture : but if any have a mind rather to do it 

 by the chemical analysis, this is not to dissuade them. 



An Account of a Booh, entitled Geometria Organica, sive Descriptio Linearum 

 Curvarum Universalis. Auctore Colino Maclaurin, R.S.S. N^364, p. 38. 



The design of this treatise, is to examine the various methods proposed by 

 mathematicians, for describing geometric curves ; and at the same time to de- 

 monstrate a new one, far more general than any hitherto published ; founded 

 on those theorems proposed by our illustrious president, at the end of his enu- 

 meration of the lines of the third order. 



The great improvements that have been made by most of the other modern 

 geometricians, have related chiefly to the lines of the infinite order; they have 

 been so fond of applying their new methods to mechanic and exponential curves, 

 (which ought to give place to those that are more strictly geometrical) that they 

 have neglected to cultivate geometry after the most regular manner. The 

 writers on these subjects commonly rise at once, from considering the lines of 

 the second order, or conic sections, to those of the infinite order, overlooking 

 all the intermediate ranks. And hence it was, that all the orders of geometric 

 curves lay unregarded, without the known limits of geometry, besides the first 

 two, and a few of the superior curves that had been considered with some par- 

 ticular views, till that great author, by enumerating the lines of the third order, 

 enlarged the bounds of geometry, and enriched it with almost 70 new curves. 

 Their properties, which he has given, and the manner of describing such of 

 them as have a punctum duplex, have almost brought them on a level with 

 the lines of the second order ; which alone had long usurped the place in 

 geometry. 



After this great example, it is attempted in this treatise, to give a universal 



