VOL. X.] PHILOSOPHICAL TRANSACTIONS. 237 



more favourably of the professor's instruments, or lunar observations, which he 

 'shows are very erroneous. 



jin jiccount of two Books. N° 118, p. 435. 



I. Jacob! Barneri, Ph. et Med. D. Augustani, Prodromus Sennerti* Novi, 

 sen Delineatio Novi Medicinae Systematis, &c. Augustae Vindelicorum. An. 

 1674, in 4to. 



The works of Sennertus being in the library of most physicians, it would be 

 superfluous to insert an account of his system here. 



II. A Description of Helioscopes, and some other Instruments, made by 

 Robert Hook, F. K.S. London, 1675, in 4to. 



Of the contents of this book, as far as they relate to the instruments therein 

 described, I need say nothing here : I shall only touch upon some passages 

 in the postscript, in which I find one of our tracts concerned. The post- 

 script takes the liberty of reflecting on a passage in N° 112 of these Trans- 

 actions, viz. about the invention of applying a spring to the balance of a watch ; 

 finding fault with the same for not having noticed, that " this invention was 

 first found out by an Englishman, and long since published to the world," and 

 complaining thereupon of '' unhandsome proceedings." 



As the former part of this accusation directly concerns the editor of the 

 Transactions, and the latter is so ambiguously worded, as that it may be re- 

 ferred to the said author, as well as to the French Journal des Scavans, it was 

 thought fit to acquaint the impartial and candid reader with the plain truth of 

 this matter. 



It is certain then, that the describer of the helioscope, some years ago, 

 caused to be actually made some watches of this kind, yet without publishing to 

 the world a description of the same in print; but it is as certain that none of 

 those watches succeeded, and that nothing was done since to mend the in- 

 vention, and to render it useful, that we know of, until M. Huygens sent 

 hither a letter, dated Jan. 30, 16-^, acquainting us with an invention of his of 



♦ This celebrated teacher of physic, who, from being the son of a shoemaker, came to be rector 

 of the university of Wittemberg, and physician to the Elector of Saxony, v/as bom at Breslaw in 

 1572, and died at Wittemberg in l637, aged 65, during the prevalence of a pestilential epidemic of 

 which he caught the infection. His collected works amount to 2 volumes folio. They exhibit a view 

 of the opinions and observations of philosophical and medical writers from the days of Hippocrates 

 and Aristotle unto the beginning of the 17th century. There is more of erudition than of originality 

 in his works, and some will doubtless think that he occupied himself too much witli the doctrines of 

 the ancients. He promoted, however, the cultivation of chemistry in Germany, being the first who 

 read lectures on that branch of experimental knowledge in the university of Wittemberg. Anaong 

 the practical dissertations of Sennertus, those on fevers are esteemed the best. 



