1 28 Reviews and Notices respecting New Booh, 



Electrical Society of London ; and the work now before us being' 

 announced as the production of the Secretary of that Society, we 

 oj)ened it with anxious expectation, to see how the national honour 

 would be sustained by a personage placed in so conspicuous a station. 

 Every one would of course not merely give credit to such a person 

 for knowing something of what he was writing about, but expect 

 from him some addition to our stock of knowledge ; public attention 

 having been directed to the work by advertisements, fortified by the 

 following eulogium, from no unfriendly hand, in the Atlas : " This 

 treatise exhibits the first attempts to call attention to the extraordi- 

 nary relations between the electrical conditions of the atmosphere 

 and the human body " [most extraordinary indeed, as we shall find] ; 

 " audit combines the rapid spirit of composition with the accuracy of 

 cautious research, vigour and eloquence of expression with the 

 strength of deep thinking." Of one of these subjects of panegyric, 

 " the rapid spirit of composition," it might seem that only the author 

 himself could well be cognisant ; but as it has been our fortune to ob- 

 tain a glimpse of Mr. Leithead's method, we shall give our readers the 

 benefit of it. They will no doubt recollect, as we happened to do 

 while perusing Mr. Leithead, the excellent treatise on electricity by 

 Dr. Roget in the Library of Useful Knowledge, making two numbers, 

 or 64 pages, out of which we cannot help suspecting that the worthy 

 Secretary has manufactured the first 120 pages of his book. At least 

 the coincidence between the two is throughout nearly as remark- 

 able as that which the following collation exhibits. 



Library of Useful Knowledge. Mr. Leithead. 



(§63) From what has already been P. 49. From what we have already said 

 explained of the general laws of electri- respecting the general laws of electri- 

 city, the mode in which these machines city, the modus operandi of these ma- 

 act will readily be understood. The chines will be readily understood. By 

 friction of the cushion against the friction between the cushion and the 



glass cylinder produces a transfer of glass a transfer of the electric 



electric fluid from the' former to the fluid takes place from the former to the 



latter; that is, the Cushion becoming latter; the cushion becoming 



negatively, and the glass positively, elec- negatively, the glass positively, elec- 



tiifled. The fluid wliich thus adheres trifled. The fluid which adheres 



to the glass, is carried round by the to the glass, is carried round by the 



revolution of the cylinder; and its revolution of the cylinder; its 



escape is at first prevented by the escape being at first prevented by the 



silk flap, &c. silk flaps, &c. 



To exemplify further his modus operandi (a favourite expression 

 with the Secretary), we give two other sections from Dr. Roget, in- 

 terlining them with a few alterations of phrase here and there, which 

 if substituted for what stands under them in the text, will give us 

 precisely the product of Mr. Leithead's " rapid spirit of composition, 

 accuracy of cautious research, vigour and eloquence," &c. &c. &c. 



Library of Useful Knowledge. 

 Leithead, ip. 61. electricity along 



" (§. 86.) The passage of (the electric fluid through) a perfect con- 

 It when the 

 ductor is unattended with light. (Light) appears only (where there 



