VOL. XVII.] PHILOSOPHICAL TRANSACTIONS. 60l 



this propagation being either retarded or accelerated in a diaphanous body, as 

 glass, &c. does, upon its going out of that medium, acquire again the same de- 

 gree of velocity it had before it came on, there being no new impulse or im- 

 pediment to alter the velocity it had in the other medium ? 



5. Why mercury, being so pure, simple and homogeneous a fluid, is almost 

 the only one that is not transparent? 



6. Whether the reflection of light on the surfaces of glass, water, and the 

 shade of the most perfect pellucid being always very discernible, be not argu- 

 ments that the beams pass their media with more difficulty than they do the air? 



7. Whether any texture of atoms of the same materia prima can be supposed 

 to answer to the phaenomena of the pellucidity of heavy and opacity of light 

 bodies ? 



8. Whether, if light (as it is most likely) be a tremour, shake, or undulation 

 of the aether, as sound is of the air ; and if the aether do consist of so rarefied 

 parts, as to penetrate all bodies with full liberty, as is generally supposed ; most 

 if not all bodies ought not to be transparent? 



9. Whether the matter of the universe be not of several kinds in minimis, 

 and not constituted by the various texture and coalition of the same sort of 

 atoms, as it has been held by the Epicurean and Atomical philosophers, which 

 at present obtain in the world. 



An Account of two Books. — 7. Pharmacopoeia Bateana; or. Bate's* Dispensa- 

 tory. Translated into English by fVilliam Salmon, Professor of Physic; 

 London, 1 694, Svo. N° 206, p. 1000. 



Bate's Pharmacopoeia, at the time of its first publication, was considered, 

 although it contains many absurd remedies, to be a valuable collection of extem- 

 poraneous medical formulae, and accordingly it soon went through many editions. 

 But along with pharmaceutical chemistry, the art of prescribing has of late 

 undergone such an entire change, that the Pharmacopoeia Bateana is not of the 

 least use to modern practitioners of physic. By way of apology for publishing 

 this book in English, the translator cites the examples of Hippocrates, Galen, 

 Celsus, and others, who all published a system of physic in their own languages; 



* Dr. Gteorge Bate was bom in 16O8, and was educated at Oxford, where he graduated and prac- 

 tised for several years, but afterwards removed to London. With more address than principle, he 

 •ided, as best suited bis interested views, at one time with the royal, at another with the republican 

 party ; being successively physician to Charles I. to Cromwell, and to Charles II. He died in 1669. 

 Some years after his death, an apothecary of the name of Shipton published, as his prescripiions, the 

 above-mentioned collection of formulae, entitled Pharmacopoeia Bateana. Dr. Bate was, moreover, 

 author of several political tracts. 



VOL. III. 4 H 



