/ Intelligence and Miscellaneous Articles. 411 



perfect and obscure. He then explained it ; but we regret our in- 

 ability to express it adequately. It appeared to depend on the con- 

 ception of points, absolutely fixed in space, and endowed with cer- 

 tain properties and powers of transmission, according to determined 

 laws. — Prof. MacCullagh had indulged in speculations allied to, and, 

 as he conceived, involving this very conception of Sir W. Hamilton, 

 and had even followed out some of its consequences, by reducing it 

 to a mathematical form — the conception was of double points, or 

 poles, transmitting powers — but he had abandoned it as mere specu- 

 lation. — Sir D. Brewster thought these speculations tended to re- 

 press experimental research, and to turn men's minds from what 

 was solid to what was fanciful. — Sir J. Herschel considered that 

 there could be no true philosophy without a certain degree of bold- 

 ness in guessing ; and such guessing, or hypothesis, was always ne- 

 cessary in the early stages of philosophy, before a theory has become 

 an established certainty; and these bold guesses, in their proper 

 places, he conceived, should be encouraged, and not repressed. Sir 

 W. Hamilton's conception, he thought, perfectly clear in its meta- 

 physics, and should not be thrown overboard merely because it was 

 mataphysical. ' 



USE OF IRON WIRE FOR SECONDARY ELECTRO-MAGNETIC COILS. 



Mr. J. E. Ashby, B.A., of University College, London, informs us 

 that fine iron wire covered with cotton may be substituted for cop- 

 per in secondary coils, with an increase rather than diminution of 

 effect, at less than l-6th of the price, and with a great saving of 

 space. Half a pound of this wire costs Is. 3d. and measures nearly 

 1400 feet. 



With secondary coils so constructed, he has been able, he states, 

 to make the magnetic spark pass through nearly l-100th of an inch 

 between two wires, as in Mr. Crosse's experiment ; and by means of 

 a battery of about four square inches negative plate and a length 

 of only 1 100 feet in the secondary, to excite a current in the primary 

 coil. Mr. Gassiot, Mr. Ashby observes, used for the same purpose 

 2100 feet of copper wire and twenty large cells of Mr. Daniell's 

 battery. 



NON-CONVERSION OF CALOMEL INTO SUBLIMATE BY THE 

 ALKALINE CHLORIDES. 



We have in our last Number adduced the numerous experiments 

 of M. Mialhe on the conversion of calomel into corrosive sublimate. 

 The following notice, denying such change, signed Lepage, is from 

 the Journal de Chimie Medicate for September. 



M. J. Righini d'Ollegio, in a notice relative to the action of the 

 vapour of water on calomel (Jvurnalde Chimie Medicate, Avril 1842), 

 gives the result of an experiment which he performed in order to 

 ascertain if, as had been lately announced, calomel is converted into 

 corrosive sublimate, by the influence of the alkaline chlorides, at the 

 temperature of the human body. M. Lepage states that the result 



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