216 Notices respecting New Books. 



Pneumatic Institution at Bristol, established by Dr. Beddoes for the 

 purpose of investigating the medicinal powers of factitious airs or 

 gases. " It is now general!}' acknowledged," says Dr. Paris, " that 

 the Art of Physic has not derived any direct advantage from the 

 application of a class of agents, which undoubtedly held forth the 

 fairest promise of benefit." " The investigation, however/' he con- 

 tinues, " into the nature and composition of the gases paved the 

 way to some new and important discoveries in science ; so that to 

 borrow a Baconian metaphor, although our philosophers failed in 

 obtaining the treasure for which they so eagerly' dug, they at least, 

 by turning up and pulverizing the soil, rendered it fertile. The 

 ingenuity of the chemist will for ever remain on record; the phan- 

 toms of physicians have vanished into air. " 



In a letter to Mr. Davies Gilbert, dated Clifton, November 12, 

 1798, Dav}' says, " We are printing in Bristol the first volume of 

 the West Country Collections, which will I suppose be out in the 

 beginning of January." Dr. Paris informs us that " the work an- 

 nounced in the above letter was published in the commencement 

 of the year 1799, under the title of ' Contributions to Physical and 

 Medical Knowledge, principally from the West of England; col- 

 lected b}' Thomas Beddoes, M.D.'" 



The following are Dr. Paris's observations on this work : " The 

 first two hundred pages, constituting very nearly half the volume, 

 are the composition of Davy, and consist of essays ' On Heat, Light, 

 and the Combination of Light;' ' On Phos-oxygen, or Oxygen and 

 its Combinations ;' and ' On the Theory of Respiration.' 



" His first essay commences with an experiment, in order to show 

 that light is not, as Lavoisier supposed, a modification or an effect, 

 of heat, but matter of a peculiar kind, sui generis, which, when 

 moving through space, or in a state of projection, is capable of be- 

 coming the source of a numerous class of our sensations." 



" A small gunlock was armed with an excellent flint, and on 

 being snapped in an exhausted receiver, did not produce any light. 

 The experiment was repeated in carbonic acid, and with a similar 

 result. Small particles were in each case separated from the steel, 

 which, on microscopic examination, evidently appeared to have un- 

 dergone fusion. Whence Davy argued, that light cannot be caloric 

 in a state of projection, or it must have been produced in these ex- 

 periments, where heat existed to an extent sufficient to fuse steel. 

 Nor, that it can be, as some have supposed, a vibration of the ima- 

 ginary fluid aether ; for, granting the existence of such a fluid, it 

 must have been present in the receiver. If, then, light be neither 

 caloric in a state of projection, nor the vibration of an imaginary 

 aether, it must, he says, be a substance sui generis." ' 



" With regard to caloric, his opinion that it is not, like light, 

 material, has been alread)' noticed. In the present essay he main- 

 tains the proposition by the same method of reasoning as that by 

 which he attempts to establish the materiality of light, and which 

 mathematicians have termed the ' reductio ad absurdum.' " 



" In his chapter on Light and its Combinations,'' he indulges in 



specu- 



