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to the discovery, that flame cannot pass through capillary tubes, 

 and he had the courage to ignite the most violent of explosive mix- 

 tures at the jet of Newman's blow-pipe. All know the wonderful 

 pspwers of this invention in the hands of Dr. Clarke ; and though his 

 reduction of the earths, which a few years ago would have been 

 inestimable, has not increased our certainty of their metallic na- 

 ture, without doubt, chemistry is highly indebted to him and he 

 is entitled to great praise for his activity in this investigation. 

 Yet, notwithstanding the beauty of this contrivance, I think that 

 Hare's instrument is better adapted to tlie uses of the chemist ; it 

 is, perhaps, inferior in power, but this is counter-balanced by great 

 advantages, which it is the object of this communication to indicate, 

 and at the same time to detail some of the facts which I have 

 observed. Mr. Hare's description of his blow-pipe was published 

 in the 14th vol. of Tilloch's Magazine, much of the paper is oc- 

 cupied with an inconvenient sort of gas-holder, but his account 

 of the effects of the gaseous flame is very striking, and had he 

 not added iron and plumbago to the subjects of his experiments, 

 he must have anticipated Dr. Clarke. His gases -were contained 

 in separate vessels, they were conducted from these by tubes which 

 united in a conical nozzle \ of an inch long, and the mixed stream 

 was ignited at its aperture. At first sight, it appears that no ac- 

 cident can happen, as the mixture takes place only in the nozzle, 

 but, if we consider more attentively, it may be feared, that an in- 

 equality of pressure in either of the gasometers might force its gas 

 into the other : if this takes place in that which holds the oxv- 

 gcn, it must become apparent by the extinction of the flame, and 

 may be guarded against ; but in the case of the hydrogen, we 

 have no such security, as it will burn, while at the same lime 



