Notices respecting New Books. 45 



current ceases, and therefore it cannot be the irritation caused 

 by it that produces the sensation oflight. 



39. If light impinge on the iris only and not upon the re- 

 tina, no contraction of the iris ensues ; but if it fall upon the re- 

 tina, then the iris contracts, even if no light has access to the 

 iris itself; therefore the motions of the iris are governed by 

 sensations traversing the optic nerve, and this sensation induces 

 a current in the motor-nerves of the iris. 



40. In the motions of respiration induced by the action of 

 the atmospheric air on the incident nerves of the lungs, in the 

 contraction of the sphincters by the induction of the nerves 

 irritated by the contents of the canal or bladder, — in cough- 

 ing from irritation of the larynx, in sneezing from irritation 

 of the nose, and in many like instances, we see cases of induced 

 motion; and these facts, with those I have before adduced, may 

 at present suffice to point out the perfect analogy, if not iden- 

 tity, between the nervous and electric influences : the more ex- 

 tended details of its application to many other interesting vital 

 phaenomena in the healthy and diseased condition of organic 

 bodies will be given hereafter. 



London, Jan. 5, 1843. 



X. Notices respecting New Books. 



Lectures on Chemistry, illustrated by 106 Wood cuts. By Henry M. 

 Noad, Member of the Chemical and Electrical Societies of London ; 

 Lecturer on Chemistry ; Author of Lectures on Electricity, &c. 



WERE it possible we would gladly bestow commendation on 

 any attempt, however humble, to enlarge the boundaries of 

 science ;' but when books are presented to the public, we must, if 

 we notice them at all, speak of them as we find them. It is with 

 regret that we are obliged to withhold our approbation from the 

 work, the title of which is above given ; but we are sure that when 

 we have pointed out its true nature, the author himself will scarcely 

 be surprised at our opinion, and that the public will agree with us 

 that this book has been got up with too great haste or too little 

 knowledge ; and in some cases we think it will appear that both 

 these formidable obstacles to a successful undertaking have lent 

 their combined aid. 



We cannot afford sufficient space to notice the numerous state- 

 ments which require correction ; we shall, therefore, offer a few ob- 

 servations on the author's History of Chemistry, and then confine 

 ourselves chiefly, if not altogether, to the chapter on oxygen, as af- 

 fording numerous instances of inaccuracy on a subject of great in- 

 terest, and yet nowise complicated or difficult. 



In the historical sketch, of which the first lecture consists, an ac- 

 count is given of the labours of nearly forty chemists ; with all of 

 these but one, discordant as their theological opinions must have 



