VOL. L.] PHILOSOPHICAL TRANSACTIONS. ^ 317 



it was gathered at a certain season of the year, and that one part of the 

 cure was burying it in sand for some time. This may be tried with cassia, and 

 may perhaps take away that viscosity or gkitinous quality observed by chewing 

 it, and which is the principal mark for distinguishing it from cinnamon. As to 

 their chemical oils, I have heard many people say, that they are not distin- 

 guishable, otherwise than that from cinnamon is generally better, or, as it may 

 be called, stronger than that from cassia ; and accordingly bears a better price. 

 But the Dutch company's chemist at Batavia, if I may give him this title, in- 

 formed me that they are essentially different, and plainly distinguishable. But I 

 must confess myself very doubtful of the knowledge or veracity of this chemist, 

 and strongly suspect that they are no otherwise different than in goodness, as 

 many other oils drawn from the same subject are. 



In Persia, I think they make not so great a difference between them as else-, 

 where ; and I myself, for want of cinnamon here for some months past, made 

 use of the fine quilled cassia ; and the difference I observe between them I 

 imagine to arise rather from the greenness and want of dryness in the cassia, 

 than any thing else, or perhaps from the method of curing it : for if there hap- 

 pens to be a little too much cassia put into my chocolate (and other things I use 

 in it,) a little bitterish taste arises, something like what we meet with in most 

 barks ; though I do not remember to have observed this of cinnamon : but as to 

 its boiling to a jelly, as Quincy mentions, I find no such thing, and think it 

 bears boiling as well as cinnamon. Nor do I think its distilled water more sub- 

 ject to an empyreuma than that of cinnamon. 



I have inquired of the country people here who bring it us, and they tell me 

 the finest sort is the inner bark of the small branches : and indeed that it is the 

 inner bark, I think, is evident in cinnamon as well as cassia ; no outer bark of 

 the youngest branches of any tree having, in my opinion, that smooth surface 

 observable in both these barks. 



END OF THE FIFTIETH VOLUME OF THE ORIGINAL. 



Art. I. On the Greatest Effect of Engines with Uniformly Accelerated Motions. 

 By Francis Blake, Esq., F.R.S. p. 1 . FoL LI. Anno \ 7 5g. 



The writers on the maximum of engines, or the greatest effect possible in 

 any given time, have supposed the working parts of the machine to retain their 

 direction, and be uniformly moved by the force of a current. They have there- 

 fore considered only the case of a uniform rotation, as in the actjon of grinding -, 

 where the impediments and impulses being brought to a balance, the impulses 

 are only sufficient to prevent a decay in the generated motion. And, on that 



