-50 Mr. 0. C. Hutchinson on a convenient Source 

 Add together the two readings. The sum will be : — 



For half-gill 10*0 



„ gill 20-0 



„ half-pint 30-0 



„ pint 40-0 



„ quart 50*0 



„ half-gallon 600 



„ gallon 70*0 



„ peck 80-0 



„ half-bushel 90*0 



„ bushel 100-0 



XXVIII. On a convenient Source of Heat for Chemical Ope- 

 rations. By Christophek Clarke Hutchinson, Assoc. 

 R.C.Sc.L 8fc* 



MOST chemical laboratory operations require some source 

 of heat, which should be capable of being readily ap- 

 plied and varied to meet the requirements of each individual 

 case. 



This is effected, in most instances, by the combustion of 

 coal-gas in an ordinary Bunsen burner. Circumstances may, 

 however, debar the operator from the use of coal-gas. He 

 may be called upon to carry out some process, e. g. in the 

 workings of a mine, at the side of a mineral spring, in the 

 collection of water, gas, or air, in field blowpipe work, &c; or 

 finally, his laboratory may have to be hastily improvised in a 

 country district (especially in a partially civilized country) 

 where coal-gas is not obtainable. 



He has then to fall back upon the older and more crude 

 methods, such as the spirit-lamp, the wind- or charcoal-fur- 

 nace, &c, which are at the best incovenient, and often fail to 

 give satisfactory results in their employment. None of them 

 can be readily varied according to the desired temperature ; 

 and they require some dexterous manipulation, or a consider- 

 able amount of attention. 



To supply this want, a simple method suggested itself to 

 me which I believe may be of utility under some of the condi- 

 tions above enumerated. It will be found efficient as well as 

 simple, the cost both for material and apparatus being small, 

 in addition to which it can be rendered exceedingly port- 

 able. 



It is well known that many of the common forms of the 

 liquid hydrocarbons are easily vaporizable, even at the ordi- 



* Communicated by the Author. 



