148 Notices respecting New Books. 



jectured that the formation and carrying away of carbonic acid 

 exercises only a subordinate influence in the matter." 



Two pieces of charcoal, one of which is less heated than the 

 other by the flame, deport themselves exactly as a pair of pla- 

 tinum wires under the same circumstances. Silver, copper, 

 brass and zinc, have been also examined, all of which exhibited 

 the same electrical deportment as platinum when brought into 

 contact with heated air. 



The following conclusions are drawn from the experiments 

 above described : — 



1. Gaseous bodies which have been rendered conductible by 

 strong heating are capable of exciting other conductors, solid as 

 well as gaseous, electrically. 



2. When a thermo-electric circuit is formed of air, hydrogen 

 or carburetted hydrogen, alcohol vapour, charcoal, or finally a 

 metal, whether combustible or incombustible, an electric current 

 is developed, which proceeds from the hottest place of contact 

 through the air to the less warm place. 



3. The development of electricity which has been observed in 

 processes of combustion, and particularly in flame, is due to 

 thermo-electric excitation, and stands in no immediate connexion 

 with the chemical process. 



4. The products of combustion do not therefore by any means 

 occupy the relation to the binning body which has been assumed 

 by Poiullet ; if positive electricity rises with the ascending gases, 

 it is only in the degree in which the burning body and the air 

 exterior to the place of combustion, or rather exterior to the 

 place of hottest contact, are connected by a proper conductor. 



XXIII. Notices respecting New Books. 



A Treatise on Problems of Maxima and Minima, solved by Algebra. 

 By Ramchundra, Teacher of Science, Delhi College. Calcutta. 

 8vo. 1850. 



'"I^HE time will come when Hindu antiquaries will search out the 

 J- history of the revival of algebra in their country, by the agency 

 of its introduction from the West. It will then perhaps appear 

 worthy of note, that one of the earliest native attempts to write 

 algebra in the European form is also an attempt to show that the 

 domain of pure algebra can be extended, without prejudice to the 

 superior facility of the differential calculus and of its equivalents. 



The author's method, in general terms, is as follows : — If \px be 

 a function of the ?/th degree, which is to be made a maximum or 

 minimum, it is assumed that x"~ 2 -\-ax"~ 3 -\- ... is a divisor of \px — r. 

 The division being made, the identification of the remainder with 

 zero leads to n — 2 equations between the n — 1 quantities r, a, &c. ; 



