218 Notices respecting New Books. 



loses the projectile form, and becomes perceptible as light. It is 

 extremely probable, he adds, that the great quantity of this fluid 

 almost every where diffused over our earth is produced by the con- 

 densation of light, in consequence of the subtraction of its repul- 

 sive motion by black and dark bodies; while it may again recover 

 the projectile force by the repulsive motion of the poles, caused by 

 the revolution of the earth on its axis, and thus appear again in the 

 state of sensible light; and hence the phoenomenon of the Aurora 

 Borealis, or Northern Lights." 



" In considering the theory of respiration, he supposes that phos- 

 oxygert combines with the venous blood without decomposition, but 

 that on reaching the brain, the light is liberated in the form of 

 electricity, which he believes to be identical with the nervous fluid. 

 On this supposition, sensations and ideas are nothing more than 

 motions of the nervous £Bther; or light exciting the medullary sub- 

 stance of the nerves and brain into sensitive action !" 



" He thinks it would be worth while to try, by a very sensible 

 electrometer, whether an insulated muscle, when stimulated into 

 action, would not give indications of the liberation of electric fluid, 

 although he suspects that in man the quantity is probably too small, 

 and two slowly liberated, to be ascertainable. In the torpedo, and 

 in some other animals, however, it is unquestionably given out per- 

 ceptibly during animal action." 



"When any considerable change takes place in the organic matter 

 of the body, so as to destroy the powers of life, new chemical at- 

 tractions and repulsions take place, and the different principles of 

 which the body is composed enter into new combinations. In this 

 process, which is called putrefaction, Davy, in pursuance of this 

 theory, thinks that in land animals the latent heat of the S3'stem 

 enters into new combinations with oxygen and nitrogen, but that 

 in fish no such combinations occur, and hence the luminous appear- 

 ance which accompanies their putrefaction." 



Dr. Paris very justly characterizes these essays as extraordinary ; 

 but " I am not quite sure," he adds, " that amidst all the meteors 

 of his fancy there may not be a gleam of truth. I allude to his 

 theory of Respiration : it certainly does not square with the phy- 

 siological opinions of the day ; nor did that of Newton, when he 

 conjectured that water might contain an inflammable element ; but 

 it was the refraction of a great truth, at that time below the hori- 

 zon." We admit with Dr. Paris, that the theory o? phos-oxygcn and 

 luminated pkos uxi/gen has scarcely a parallel in extravagance and 

 absurdity, and with him we also " happen to know that in after life 

 Davy bitterly regretted that he had so committed himself; any 

 allusion to the subject became a source of painful irritation." — 

 This was precisely the effect produced upon him by the notice 

 which Chenevix took of his theory in his treatise on nomenclature. 

 After all. Dr. Paris rightly observes, " the reader, however, will 

 be disposed to treat him with all tenderness when he remembers 

 that the author of these essays was barely eighteen years of age." 

 In a letter to Mr. Gilbert, dated Clifton, February 22, 1799, he 



gives 



