384 
otherwise too easily, the platinum being very soft at such high tem- 
peratures. The wire passes through a narrow, cylindrical hole in 
the bottom of the balance-case, a second hole of the same shape 
in the board B, and a third small canal in the water-screen S, 
which is continuously passed by a stream of cold water, so as to 
prevent the heat-radiation from the furnace to the balance-case. At 
its free end the wire bears a massive platinum double-conus D, 
made from iridium-free platinum; this sinker had in our experiments 
a weight of about 12,1 grams. The balance could move up-and- 
down by means of four brass pulleys /, gliding along the four iron 
bars £; it is supported by a movable pillar P?, to which at one 
side also a pulley m is fixed, resting on a thin steel cable d. By 
means of a windlass and handle // this cable can be shortened or 
lengthened, the balance being thus moved upwards or downwards. 
The board 5 can be rolled to and fro by the wheels ¢, moving 
on the iron rails fixed on A; in this way the balance can be placed 
above the furnace (, or, if necessary, it can be removed from it. 
G furthermore is a heavy iron weight, which serves for the equili- 
brium and stability of the whole apparatus, which in the neigh- 
bourhood of the furnace is firmly fixed upon a heavy table. 
Now the platinum sinker with wire is weighed in air; then the 
balance is dropped till the conus is dipped into the liquid, until the 
surface of this comes to a fix-point on the wire. The temperature 
of the liquid is determined by means of a thermoelement placed in 
it quite near to the sinker, by measuring its electromotive force with 
the potentiometer-arrangement always used in this laboratory‘). By 
measuring the force, with which the sinker is driven upwards, if 
the balance ean swing freely, the specific weight of the liquid can 
be calculated, and all necessary corrections can be taken into account. 
The described method was previously tried by means of a number 
of organie liquids of known density. The result was, that the thus 
obtained data agreed completely with those obtained by means of 
the pyenometer, as far as the dependence of the density on the 
temperature is concerned; moreover also the absolute values appeared 
to be the same in both cases, if only a correction was taken into 
account for the capillary influence of the liquid on the wire, which 
e.p. appeared to be directly propertional to the specific surface- 
energy x of the liquid at every temperature. In the-case of the 
wire used by us this correction appeared to be only slightly more 
than about 0.0001 gram per Erg. This amount must be added 
1) FP. M. Jarcer Eine Anleitung zur Ausführung exakter physiko chemischer 
Messungen bei höheren Temperaturen. Groningen, 1913, p. 16—19. 
