(31) 
perature!) above the highest occurring temperature of the water 
supply are made by admitting a regular current of water of constant 
temperature. 
§ 2. The reduction of the variation of temperature in flowing 
water. The arrangement for obtaining flowing water at constant 
temperature by VAN ELDIK in Communication N°. 39 (Proceedings 
May 29% ’97 p. 22 and fig. IV) has served as my starting point. 
The disadvantage of using large quantities of water does not matter 
much in my arrangements as the same water is used to move the 
stirring apparatus. Important modifications had to be introduced 
into VAN ELpIk’s arrangement because it only reduced the variations 
in the temperature to 0.1 deg. C, and this is insufficient for my 
purpose (comp. § 1). 
The most important of these modifications is the construction of 
a large well packed mixing bath, containing over 84 liters of water. 
: ; 1 
The water streams into this from a smaller heating bath of a 
the capacity and is mixed with the larger quantity and well stirred ; 
if now in the heating bath the temperature is only aliowed to vary 
within given limits, this variation is reduced in the mixing bath to 
one sixth of its value*). Moreover a more reliable thermoregulator 
was constructed to regulate the temperature of the heating bath. 
The apparatus is shown on the annexed plate. The tube K con- 
ducts a little more water than is needed to the overflow A, the 
superfluous water flowing away by the tube Z. From the funnel B 
the water runs to the heating bath D, to the mixing bath F’ and 
through the indiarubber tube G, to the observation bath H, whence 
it is conducted by the outlet-tube I. The difference of level amounted 
to 75 c.m., and 800 ec. of water ran through per minute. The con- 
necting tubes H and G, are protected from cooling by a coating of 
pure wool; the mixing vessel is surrounded by a second vessel and 
the space between the two is filled with pure wool. The cover of 
the inner vessel is provided with 4 openings M, N, Oand P; ther- 
mometers are passed through corks in M and N, 9 and P are pro- 
1) For the investigation of the Isothermal of hydrogen at ordinary temperature 
I have chosen 20° C. 
2) It would have been even better if the heating bath had been smaller and the 
mixing bath larger; but as apparatus of the description mentioned was at hand no 
change has been made in the ratio. 
