Intelligence and Miscellaneous Articles, 399 



founded ? and does not a considerable portion of light actually pass 

 through the base of the prism and emerge at its under side, even in 

 the space where the light is totally reflected, as it is usually termed? 

 May not this be owing simply to the scattering of the rays at the 

 surface of the glass, which even the most perfect polish cannot 

 wholly prevent ? 



Whilst upon this subject I may be allowed to add, Has any phi- 

 losopher examined the case of interference mentioned by Mr. Potter 

 in the Reports of the British Association for 183a, p. 378, which is 

 brought forward by that gentleman as at variance with the results 

 of the undulatory theory ? 1 must confess, as far as I understand 

 that theory, 1 do not perceive how the inference is deduced from 

 it : perhaps some of your scientific readers will throw some light oa 

 this point. 



As it seems that the theory of dispersion is, at least, in a fair 

 way to be settled by the researches of M. Cauchy (as appears 

 from Professor Powell's valuable analysis which is in progress of 

 publication in your Journal*), it would appear that the points I 

 have alluded to, adding, perhaps, the question agitated by Mr. 

 Potter as to the central stripe of the interference-bands, are the 

 only remaining points which the undulationists have to make good, 

 I trust, therefore, that my remarks may be the occasion of calling 

 forth such elucidation ; and remain, 



Gentlemen, yours, &c. X. 



DETECTION OF MINUTE PORTIONS OF SULPHUR. 



M. Boutigny states that very minute portions of sulphur may be 

 detected by mixing the substance suspected to contain it with a small 

 portion of nitre, and projecting the mixture into a red-hot porcelain 

 capsule. The saline matter is to be washed out with distilled water, 

 saturated with muriatic acid, and treated with muriate of barytes ; 

 the precipitate formed, if it be sulphate of barytes, is to be mixed with 

 a little soda and heated upon charcoal ; the residue is to be placed 

 upon a strip of silver and moistened j sulphuretted hydrogen will 

 escape in sufficient quantity to be perceptible by the smell, and to 

 form a black spot of sulphuret on the silver.— ,/ow?'waZ de Chimie Me- 

 dicale, Jan. 1835. 



CONVERSION OF SUGAR INTO FORMIC ACID AND ULMIN. 



M.Malagutti heated a mixture of 100 parts of sugar, 300 of water, 

 and some grammes of nitric acid ; after some hours boiling a brownish 

 deposit was formed : after continuing the ebullition for some days 

 the saccharine matter disappeared, and formic acid was produced j 

 the deposit on examination appeared to be ulmin. — Ibid. p. 49. 



SCIENTIFIC BOOKS. 



Transactions of tlie Zoological Society, Part III. vol. i. 



A Guide to Geology. (Second Edition.) By Professor Phillips. 



The Earth ; its Physical Condition and most remarkable Phaeno- 

 mena. By W. Mullinger Higgins, Fellow of the Geological Society, 

 and Lecturer on Natural Philosophy, Guy's Hospital. 



* Concluded in our last Number. — Ei>it. 



