470 Intelligence and Miscellaneous Articles. 



the gfanite and slates ; their contents, however, varying in tlie dif- 

 ferent rocks. 



Being myself confined by circumstances to a district of primary 

 rocks, I beg permission, through the pages of your Journal, to 

 inquire whether any of your geological readers have ever traced 

 the same vein from a primary into a secondary rock ? If so, what 

 were the attendant phaenomena? Were the contents identical in 

 both formations ? Or do the veins which traverse each of these dif- 

 ferent formations, respectively terminate when falling in contact 

 with rocks of the other series ? 



In the present imperfect state of our knowledge of the phaenomena 

 of metalHferous veins, any information connected with the subject 

 of this inquiry cannot fail to be highly interesting ; and it strikes 

 me, that the intelligent agents of the lead mines in North Wales 

 might supply some valuable matter. I remain, &c. 



Tavistock, September 19th, 1832. W, J. H. 



NOTICE OF A NEW OXY-HYDKOGEN BLOWPIPE APPARATUS. BY 

 J. O. N. RUTTER. 



I have caused to be constructed by Messrs. W. and S. Jones, 30, 

 Holborn, an apparatus which is more simple, and at the same time 

 more effective than either Clarke's or Gurney's blowpipe ; and it 

 possesses the additional advantage of being perfectly safe. The 

 most timid may use this instrument without the slightest danger of 

 explosion. With ordinary precautions such an occurrence is abso- 

 lutely impossible. 



In Clarke's and Gurney's blowpipes it is well known that the gases 

 are mixed in their due proportions previously to changing the re- 

 spective reservoirs. In this consists their principal cause of inse- 

 curity, — to obviate which I condense the gases in separate vessels, 

 and they are not mixed until in a state of combustion. 



Excepting that the vessels I employ are larger than ordinary, 

 I may describe my apparatus as consisting of two of Clarke's blow- 

 pipes, fixed parallel to each other on a mahoganj' slab, the jets 

 being inclined so as to form an angle of about 5°, and separated by 

 a partition TrVth of an inch thick. The orifices of the jets are con- 

 siderably larger than those commonly used. 



The dimensions of the vessels are as follows : — That for hydro- 

 gen (marked Hyd. ), 10 inches long by 5 wide, and 4- deep ; that for 

 oxygen (marked Oxy.), of half the capacity of the former, viz. 

 10 inches long, 2| wide, and 4 deep. It is important that the copper 

 vessels be made very strong: this is the greatest difficulty I have 

 had to contend with. With a 9-inch syringe I can condense from 

 800 to 1000 cubicinches of hydrogen gas into the largest vessel, and 

 about half that quantity of oxygen into the vessel appropriated for 

 it. That there can be no necessity for safety-valves, safety-tubes, 

 wire-gauze, water, or oil, or mercurial chambers, must be apparent 

 to every one whom tiie present coinn)nnication may concern : 

 these are consecjuently dispensed with. The tubes which conduct 

 the gas from the respective vessels have each two stop-cocks to 



