308 Analysis of Scientific Books. 



unless that of the composition of nitrogen already before our 

 readers, be alluded to. 



Our author then touches upon moral philosophy, in which, he 

 says, " as there is no beginning to our conjectures, there is no chance 

 of their arriving at any end. If we begin to guess at all, as to the 

 nature of moral causes, we may guess about them as much as we 

 please ; for there is no reason why we should ever stop. And in 

 fact, about that which we actually know nothing, we never can, by 

 any possibility, know any thing, except through the interpretation 

 and revelation of a superior power," SfC Now all that we can 

 possibly conclude from this passage is, that the latter part of it 

 applies with singular fitness to Mr. Gurney's chemical knowledge. 



But where so much " important matter of fact" is brought 

 before us, we must not waste our space in these " shrewd con- 

 jectures and happy guesses," we therefore hasten to give our 

 readers a spice of Mr. Gurney's notions, concerning " the effects 

 of light in natural phenomena." 



In the first place he tells us, that " light as well as heat is a 

 modification of electricity," and that the various colours of plants 

 are derived from metallic oxides, undergoing various changes, 

 occasioned simply by their contact with light on the surface of the 

 plant, and that during the night plants give out nitrogen. But all 

 these " novelties" are trifling to those propounded by the truly 

 original Mr. Gurney, in respect to animal functions. He asserts, 

 and in sober seriousness too, that " the blood in animals contains 

 iron and other metallic oxides, which not only occasions its par- 

 ticular colour, but determines its fitness for regulating the functions 

 and renovating the powers of the system. Persons excluded from 

 light become first pale and sallow, and finally sickly and diseased. 

 Perhaps this may arise chiefly from the imperfect oxidation of the 

 blood, occasioned by the absence of light." " Coloured bodies 

 are all better conductors of heat than white, therefore animals 

 clothed in white under the frigid zone, are better able to bear 

 severe cold." At p. 262, et seq., there is abundance of analogous 

 talk concerning " moonlight, the cheek of beauty, magnetism, 

 sunshine, and electricity," which is offered with great diffidence, 

 " because it is only lately that I have made the matter a subject 

 of my thoughts." 



But we must draw to a close. We have elsewhere complimented 

 Mr. Gurney on his originality — his modesty induces him (p. 269,) 

 to hope that he may allude to what he has said and done, as being 

 with few exceptioi s novel and original, and may therefore meet 

 with more indulgence than if he had pursued the common and 

 beaten track ; and finally, he concludes with the following pecu- 

 liarly condescending and complacent paragraph. 



" I would beg permission, also to refer to the new matter, in the 

 way of theory, as well as of practical discovery, that I have been 



