M)G Intelligence and Miscellaneous Articles. 



previously cooled mixture of 1 measure of oil of vitriol and 5 of water; 

 and for purifying it, 1st, a solution of potash ; 2nd, a solution of 

 protonitrate of mercury; and 3rd, sticks of caustic potash. The 

 second purifier was a three-necked Woulfe's bottle, to the central 

 neck of which was fitted, 1st, a Welter's tube containing 3 inches 

 of mercury, to indicate the pressure of gas ; and 2nd, a bent tube with 

 a thin vulcanized india-rubber bag at its extremity : the bag received 

 any excess of gas which could not readily escape at the burner, and 

 its elasticity effectually prevented the pulsations and irregularities 

 in the jet of burning gas caused by the bubbling through the liquids. 



The most effectual gas-burner I have used has been formed of a 

 piece of iron gas-tubing, 8 inches long and half an inch in diameter, 

 closed at one end by a very thin plate of iron, in which were drilled 

 seven exceedingly fine holes. The holes require to be occasionally 

 cleaned by means of a very small steel broach*. 



With a generator containing \\ gallon of acid water and 3 pounds 

 of zinc, and with a pressure of gas of 1 pound per square inch, I 

 have obtained a splendid pencil of flame 20 inches long and fths of 

 an inch in diameter, which quickly melted copper wire ^th of an 

 inch thick, and melted moderate-sized platinum wire. I have found 

 it of especial value in the analysis of infusible silicates, as a white 

 heat is obtained at a moment's notice, and conveniently maintained 

 for half an hour or more. A ball of spongy platinum held about 4 

 or 5 inches above the burner when the gas is issuing at a pressure 

 of 1 pound per square inch, produces a loud roaring noise and a sin- 

 gular glow of light without igniting the gas down to the burner, and 

 forms an interesting experiment. 



The chief advantage which this apparatus appears to me to possess 

 over others, is the convenience with which it may be used when sud- 

 denly required. 



Birmingham, Oct. 22, 1860. 



ON NEW FORMS OF ACTINOMETERS. 



To the Editors of the Philosophical Magazine and Journal. 



21 Ainslie Place, Edinburgh, 



Gentlemen, August 5, 1860. 



I send a short Appendix to my paper on Actinometers in your 



Journal of July, which, as more distinctly explaining some points 



as to registry, and more particularly as to actinometry by phosgene 



gas, you may perhaps consider worthy of insertion. 



I remain, Gentlemen, your obedient Servant, 



G' J* Burnett. 



First. For the benefit of those who have not seen my paper of 1858, 

 I must state that although I have described a mode of applying photo- 

 graphic registry to a continuously acting gas-evolving actinometer, 

 it must be understood that there are great difficulties connected with 

 it, — particularly in determining what would be the direction on the 

 paper of the diagonally rising line which would be the representative 

 of a uniform actinic action, influenced as it must be by the continually 



* A plate of platinum instead of iron would probably obviate this neces- 

 sity, and be an improvement. 



