On the Electro-statical Capacity of a Ley den Phial, fy. 531 

 P,p',t, melt' be observed in various experiments of this kind 



culated. V e then have, by an application of (13) to the results 

 of each experiment, an equation showing the difference between 

 the mechanical energies of a pound of afr in two particular sue 

 dfied states as to temperature and density. All the pa t X 

 equations thus obtained may be used towards foxing or fo 



masTnf n? ' & ^ ° f ^ ValUeS ° f the mechanica l ene|y of a 

 mass of air at various temperatures and densities. ^ 



t mm thrlnk theair 1 onleavia g the narrow passage be made 

 trical LZ °? S !Tu aI P^ 6 immersed ^ water in a calorime- 

 trical apparatus, and be so brought back exactly to the primitive 



fiBTE? S P Sh °^ d ^^ aCC ° rdin « t0 Kyle's ff£a! 

 notte s law, p'u <-pu = 0; and if H denote the value of Q in this 

 particular case (or the quantity of heat measured by mean of 

 the^calorimetric apparatus), the general equation (l 6 f takes the 



#«',/) = 0(M)-(JH + S) .... (18). 



t I uti n for i L w ^ I ; egle l c !.^ a ^ probabI y **■■«* ™* x™ substi- 

 tute ioi <j>{ u> t) and <f>(u', t) expressions deduced from (9), we find 



which agrees exactly with the expression obtained by a synthe- 

 n^lZtrt " Same FmCipH m ^ f "- 



S7t I 1 ^i ectro - st f cal Opacity of a Leyden Phial and 

 1 a f TeIe g a P\ JV ™ insulated in the axis of a cylindrical Con- 

 ducting Sheath. By Professor W. Thomson*. 



^HE principles brought forward in the preceding articles On 



J- the Uniform Motion of Heat, &c., enable us with great ease 



to investigate the - capacity t » of a Leyden phial with either air, 



MotionXlSt'lr ^ Addition c al ,.^ te tot ^ papers "On the Uniform 

 M «.i T Homogeneous So id Bodies, and its connexion with the 

 of E rn- h r" 7 ftSf 6 ^?** "id "On the Mathematied Theory 

 rLi V. '" Ju i uillhm »» i" only not in time to be appended totiS 



XS\ «■* ESS/* 1 ? a,,I,enrod in thePhitowphClfa^Sj 

 vol. v, ,,. 6 u June 1854, and vol. viii. ,,. 42, July 1854. 



the infllZ' (P , hll ;, Mi 'K- J, !" e 1863) for any Conductor (.Ubied or not to 

 the .nflue.ee of other conductors), „ s the quan.m of clectn -ily which it 

 takes to charge it to unit potential 



2M2 



