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sien and become, therefore, negative; now we shall consider those 
cases more in detail. 
The first of those three quantities which becomes negative 
when y diminishes, is 
(AHM)z=y (He — Ha) 4u, + 0 — wu Ha — Ar. 
When (AV)z= y (Ve — Va) du Vn + (1 -- 0) an becomes 
negative, then this may however, only take place, on account of 
the large value of VG, for*very small values of y. 
(AH), can only become negative, when (AH)z is negative: this 
follows from: 
(AH), = u(OH)y+(4H)z 
in which w(4f/)y is positive. 
Consequently we distinguish four cases. 
Ge NAAST ahr (EV hg oO se (AALO a0) 
bh. (Ai <20 Sa (PLA ee : (AE Bree |) 
ce Ales (AV a Oi (Ab ee (Aa me 
d= ASZ AAR LOP es (CUE ee Lie oe 
In c and d at the same time (4J’)g is taken > 0; it follows from: 
(AV)g=y(4V)u— 2 (AV)z 
that this must be the case. 
Hence it appears viz. that for extremely small values of / [and 
only for those (AV)z may become negative] (AV )g and (AV)z 
have opposite signs. 
a. Now we have: 
(AW ars (A V47 and (A Vy =O AV EO Deze 
(AH)a, ADs, (AH), and (AH), >0; (AH)z < 0. 
When we omit the coefficients in (5), then the isovolumetrical 
reaction becomes: 
Zn HA AGS Ade Os (SO 
(Z) (LZ) | (4) (A 
Towards lower 7’ Towards higher 7’ 
If follows from (6) for the isentropical reaction : 
Z4+MHt+At+G2L (Lo pr EO EO 
(L) | Z) (Zn) (A) ) (G) 
Towards lower P | Tee higher P 
It follows from both these reactions that the curves must be 
