ae 
1888.] 173 [Hunt. 
of oxygen portions (O = 16.0), plus the number of chlorine or fluorine 
portions. We have for example :— ‘ 
| Ds 
? WOrSteTIIGy cha. es Sivlo.O7 == 140 + S00. 65. aes, 1 OU 
Caleitewns ou. sao, <CCaQ, = 100, = 6.52. iad dak voi 1000 
Katstenité,, s9i.c, CHO, = 136 = 8... 17.00 
Gy PSM. 30: ieee es DOdO (HO). == 173-19... 14.88 
Apatite... ais. 0. oF, 0a,O,)) Cal, = 908 50,2... 18.16 
“In the writer’s late essay on A Natural System in Mineralogy, the 
values of p have been thus determined. These silicates are there repre- 
sented by a new notation, which employs symbols in small letters to rep- 
resent quantivalent ratios ; the combining weights of the elements being 
divided by their valency, and in all cases followed by their coefficients. 
The formula of forsterite thus becomes (mgjsi,)o, that of orthoclase, 
(k,al,$i,.)0y¢, and that of topaz, (alysi,)o,f,. 
‘‘While a similar unit is equally applicable to all haloid species, it has 
j been found more convenient for the metalline species which constitute 
| Class I, including unoxydized metals and their compounds with one an- 
other and with arsenic, antimony, sulphur, selenium and tellurium to 
divide the formula by the sum of the valencies therein represented ; so 
that for all such species the unit p gives not the mean integral weight of 
an oxygen compound in which O = 8, but that of the element, corre- 
sponding to S = 16, to Fe = 28, to Ag = 108, to As = 25, Sb = 40, and 
( Bi,= 69.3,”’* represented respectively by s,,: fe,, ag), as,, 8b,, bi,. 
4, The law of crndensation and of expansion by volumes, familiarly 
known in the chex):stry of gases and vapors at ordinary pressures, is, as the 
writer has endeav red to show, still further exemplified in the case of the 
very dense vapors into which, under much greater pressures, liquids like 
water, alcohol, hydrocarbons, and theoretically, all chemically stable 
liquids, pass when heated sufficiently ; that is to say above their so-called 
critical points, when they necessarily assume the vaporous condition. The 
conversion of all gases and vapors, by reduction of temperature and aug- 
mentation of pressure, into liquid and solid forms, helps us to understand 
that the same laws of combination by weight, and of condensation or in- 
: tegration of volume, apply alike to gases and vapors on the one hand, and 
to liquids and solids on the other. The relation of condensation (repre- 
sented by specific gravity) to equivalent weight, which thus becomes a 
fact of fundamental importance, is shown by comparing the quotient got 
by dividing the received equivalent (so called atomic or molecular) weight 
by the specific gravity of the body, as determined for all liquid and solid 
species, taking water as unity, as in the formula p + d==». The equiva- 
lent weight 7p is, as we have seen. that deduced from the empirical chemi- 
cal formula calculated from hydrogen as unity. 
* A New Basis for Chemistry, 2d Edition, § 139; also the author on Chemical Integra- 
tion, American Journal of Science, August, 1887. 2 
