Some results of Experiments instituted with Lucifer Matches. 355 



or 1°. We may in the same way adapt the formula to Fahren- 

 heit's scale. 



When x is expressed in terms of the natural scale of tempera- 

 tures, we have with the previous values of a, b, and c 2 , merely to 

 divide b and c 2 each by 100. 



For example, in this case we should have for alcohol 



a = -3538069, 

 b =6-175750, 

 c 2 = 3-990727, 



and similarly for the other liquids. 



When the temperatures are expressed on Fahrenheit's scale, 

 we should have 



c" fc" 



b-x (f 6 + 32) -(fa? + 32) 



9 



Putting the degrees on Fahrenheit's scale =a/= - x + 32, we must 



9 ° 9 



multiply c 2 and b by -z, and add 32 to the product -^b for the 



required formula. 



For example, the formula for the volumes of alcohol, when the 

 temperatures are given in Fahrenheit's degrees #', becomes 



«L 1 Q roQn«n , 718-33086 



the volume =-3538069+ n43 . 635 _^ 



and in like manner formulae are easily obtained for the other 

 liquids when a, b, and c 2 are known for given scales. 



LI. Some results of Experiments instituted with Lucifer Matches 

 and others ignited by friction. By F. A. Abel, F.R.S.* 



TWO distinct experimental inquiries, upon which I have 

 recently been engaged, involved the chemical examination 

 of a considerable number of matches of different kinds, manu- 

 factured in London, the Provinces, Germany, and Sweden ; and 

 included determinations of the comparative susceptibility to igni- 

 tion by friction or percussion, and by heat, and of other points 

 bearing reference to the safety and keeping qualities of the 

 matches of different manufacture. Believing that the informa- 

 tion furnished by the results of these experiments may be of some 

 general use and interest, I venture to lay a brief account of them 

 before the Members of the British Association. 



* Communicated by the Author, having been read at the British Asso- 

 ciation at Newcastle-upon-Tyne in August 1863. 



