158 



Dr. Andrew Fyfe on the Comparative Value of 



when the same gas is employed. The consumption of gases, in 

 some of the towns in England that I have visited, along with the 

 pressure, was as follows. — the gases having been consumed from 

 the same burner, and with the same height of flame 



Gases 



Newcastle 

 Leeds 

 Liverpool 

 Manchester 



Time for con- 

 sumption of 

 cubic foot by 

 metre. 



t 

 50 



55 



57 

 52 



// 



30 

 55 





 30 



Pressure at 



burner in 



lOOths of 



inch 



11 



9 



8-5 

 9 



^ipiare roots 

 of pressures. 



Time calcu 



lated by 

 square root 

 of pressure. 



Difference be 



rween observ 



j and calcu 



lated time. 



3-31 



2-92 

 3 



// 



• * 



55 

 57 

 55 



• • 



40 



6 



40 



ii 





 

 3 



15 



6 



10 



The following table gives the results with gases from Scottish 

 parrot coal : 



Gases. 





Leshmahago, 

 A. ° 

 B. 

 C. 

 D. 



Time for con 

 sumption of I 

 cubic foot by! 

 metre. 



Pressure at 



burner in 



lOOths of 



inch. 



qnare roots 

 of pressures. 



85 

 59 

 69 

 65 

 90 



if 







20 



5 



50 



50 



Time calcu- Difference be- 

 lated by tween observ- 

 sqnare root ed and calcu- 

 of- pressure. lated time. 



42 



80 



64 

 72 



38 



6480 



8944 

 8000 

 8485 

 6164 



/ 



// 



/ 



ii 



61 



68 



66 



89 



30 



42 







20 



• « 



2 10 



23 



10 



1 30 



In the above tables, the experimental results agree very nearly 

 with those given by calculation ; and, accordingly, we may con- 

 sider the consumption of different gases, from similar burners, and 

 under similar circumstances, to be as the square roots of the pres- 

 sures necessary to burn them, under these circumstances; of 

 course, the times required for the consumption of equal volumes 

 will be inversely as the roots of the pressures. 



Another important circumstance still remains to be ascertained, 

 viz., as the pressure necessary for the consumption of gases va- 



spec 



? 



Is there any connection between the specific gravity of different 

 gases and the pressures necessary for their consumption, under 

 similar circumstances? 



The following table gives the results of the consumption of 

 gases under similar circumstances, along with the pressures and 

 the specific gravities, taken in the usual way. 



Gases. 



Pressure; 



in Sqimre roots 

 lOOt! is of of pressures, 

 inch. 



E 



F 



<5, 



Average of H, I 



K, L, M, N, O, 



p, a, r, s f 



68 



47 



110 



42 



8246 

 10488 



6480 



Specific- gmv 



ity by experi 



merit. 



697-6 



453 



732 



Sp incgrav-i Difference be- 

 lly calculated tween expermi i n- 

 bysuufire root tal and calculated 



bysquare 

 of pressure. 



698 

 469 



7.3 



specific gravity 



04 



60 



The results, by experiment and by calculation, above given, so 

 very nearly correspond with one another, that I think we are 











