the Laws of Viscosity. 351 



for the total variation of the pressures (see § 5) the values 



^=-2ne-(k-%n) a ,-^P, ... (la) 

 ^ = -2n/-(*-§»>-fe j =£ . . . (16) 



( l£-=-2n ff -(k-'in)o>-P^P, . . . (lc) 



dt - na T' 



(2 a) 



^ = _„,_& (2c) 



To these equations must be joined equation (4) of § 5, as 

 well as the probably verified equation h — h. These consti- 

 tute the equations to which our first method of reasoning- 

 leads us (§§ 2, 3, 4, and 5). 



The same equations may be arrived at by the second 

 method, indicated in § 7. Equation (6a), for instance, of 

 § 7 gives 



rfT=- 2M rfr-(*-3 n h*r> • • • ( 3 > 



which, by equations (3a) and (5) of the same paragraph, may 

 be written 



^ = -2ne-(k-2n)co+^ (e*--h&*). . . (4) 

 Noticing that, by (6a) and (8), § 7, 



271(6*-^*)=-^+^-^* ... (5) 



—p—p**, (6) 



we see that equation (4) becomes identical with (1 a) of the 

 present paragraph. Similarly, equations (1&), (lc), and 

 equations (2) may be established. 



The quantities e, /, g, a, fr, c, a>, as obviously also the quanti- 

 ties (pxz—p)^ {Pw"-p),(Pzz—p\,Pyz,Pzx,Pw are infinitely small. 

 Hence, making use of equation (4) of § 5 in equations (1) 



