Inflammability of Gaseous Mixtures. 195 



form the chief constituents of petrol* ; refined lamp oils are 

 composed of still heavier paraffins with a few olefines f- 

 In Table III. the limits have been calculated from the 

 formulae derived from the lighter paraffins. U and L are 

 percentages of combustible gas in air : their ratio is nearly 

 constant and may be compared with the experimental values. 



Table III. 



Compound. n. ^ . > iV GD , (D 



^ 2m+n m+(2n-l) Weal., \W 



obs. 



Methane CH 4 4 141 5-5 2-56 274 



Ethane C 2 H 6 7 105 3"08 3'41 3-45 



Propane C 3 H 8 10 7'6 212 3'58 3'39 



Butane C 4 H 10 13 5-9 162 3*64 366 



Pentane C 5 H 12 16 4'9 P31 3'74 360 



Hexane C 6 H 14 19 416 140 3"77 



Heptane C 7 H 16 22 3'61 0"95 3*80 



Octane C 8 E 18 25 349 0'84 3*80 



Nonane C 9 H 29 28 2'86 074 3'84 



Decane C 10 H 22 31 2'59 0'67 3'86 



Endecane C U H W 34 2"37 0*61 3"87 



Dodecane C 12 H 26 37 248 0"56 3"88 



Tridecane C 13 H 28 40 2-02 0'52 3"89 



Tetradecane C 14 H 30 43 1-88 0'48 391 



Pentadecane 15 H 32 46 177 045 3*91 



Mean 3*84 



Olefines are present in petroleum ; their limits of inflam- 

 mability, based on ethylene, the only gas observed experi- 

 mentally, are given in Table IV. 



Table IY. 



Compound. n rn . n rn . . — . — . 



1 C0 2 CO 2 m + n co m + ( n + l) COa L 



Ethylene C 2 H 4 6 4 17409 557 307 



Propylene C 3 H 6 9 6 12*07 396 3'05 



Butylene C 4 H S 12 8 935 3408 3404 



Amylene C 5 H 10 15 10 7*63 2'51 3"04 



Hexylene C 6 H 12 18 12 6'43 2-12 303 



Heptylene C 7 H 14 21 14 556 1-84 3-03 



Octylene C^, 24 16 4'91 162 3-03 



Diamylene C 10 H 20 30 20 396 131 3-03 



Triamylene C 15 H 30 45 30 2*67 0"88 3403 



Tetramylene ... C 20 H 40 60 40 202 0'67 301 



* " The Gas, Petrol and Oil Engine," D. Clerk, F.K.S., and G. Burls, 

 vol. ii. p. 448. t Loc. cit. supra, p. 440. 



02 



