230 Scientific Intelligence. [Sept. 



heat, the two metals will combine with a sort of explosive force, 

 scattering their melted particles off the charcoal, and emitting 

 light and heat in a very surprising manner. Then there will 

 remain upon the charcoal a film of glass ; which, by further urg- 

 ing the flame towards it, will melt into a highly transparent 

 globule of a sapphire blue colour. Also if the platinum and lead 

 be placed beside each other, as soon as the platinum becomes 

 heated, you will observe a beautiful play of blue light upon the 

 surface of the lead, becoming highly irridescent before it melts. 



Very truly yours, 



E. D. Clarke. 



III. Heat produced by the Gas Blow-pipe. 



Dr. Clarke lately in his lecture room at Cambridge, in presence 

 of the students, kept above half an ounce of platinum in a boiling 

 state before the gas blow-pipe. The mass when cool was 

 publicly weighed. 



IV. Magnetic. Iron Ore. 



A fact respecting the magnetic iron ore of Succasunny, 

 belonging to Governor Dickerson of New Jersey, is stated by 

 Col. Gibbs in Silliman's Journal of Science (i. 89), and deserves, 

 I think, to be generally known. The following is Col. Gibbs's 

 own statement. 



"The proprietor, a gentleman of distinguishedscience, informed 

 me of a singular circumstance attending it, which was too 

 important to be left unnoticed. The mine is wrought to the 

 depth of 100 feet; direction of the bed, north-east and south- 

 west ; inclination nearly perpendicular. The ore in the upper 

 part of the bed is magnetic, and has polarity ; but that raised 

 from the bottom has no magnetism at first, but acquires it after 

 it has been some time exposed to the influence of the atmosphere." 



V. On Gauze Veils. By Mr. Murray. 



(To Dr. Thomson.) 

 SIR, London, June 24, 1819. 



We are very much obliged to your ingenious correspondent 

 Mr. Bartlett, for his suggestion respecting gauze veils considered 

 as preventives of contagion. Three winters ago I found great 

 relief from using a piece of black crape before my eyes, in a snow 

 storm, and I pointed out this circumstance in the Philosophical 

 Magazine, adverting at the same time to its importance to the 

 mariner in such a peril. Bell, in his Embassy to Ispahan, found 

 that the natives of the country through which he passed were in 

 the habit of using hair cloth to prevent their eyes being injured 

 by the reflective powers of the snow. 



A handkerchief held before the mouth, &c. in the fogs which 

 obtain in this metropolis certainly prevents the unpleasant sensa- 

 tions which we otherwise experience from then - effects. 



