Humboldt State University ® Department of Chemistry

Robert A. Paselk Scientific Instrument Museum

 
from : Edwin Edser. Heat for Advanced Students. Macmillan and Co., Limited. London (1911) pp. 167-168.
 
Copyright © 1998 Richard A. Paselk
 

 

Beckmann's Freezing Point apparatus-The fact that the temperature of an over-cooled liquid rises to the freezing point when solidification occurs, has been made the basis of a method of determining freezing points. Beckmann's apparatus is shown in Fig. 77. It consists of a test tube A, provided with a side inlet tube D, and a cork through which a thermometer T and a platinum wire stirrer S2 pass. This test tube is surrounded by a larger tube B, the space between the two forming an air jacket. Both are surrounded by a larger vessel C, which call be filled with a suitable freezing mixture. The latter is kept in circulation by means of the wire stirrer S1.
 
The method of using the above apparatus is as follows:-- Some of the liquid of which the freezing point is required, is introduced ' into A, by way of the inlet tube D, which is afterwards closed by a cork. A suitable freezing mixture is introduced into C, and the whole apparatus is allowed to stand till the thermometer T indicates a temperature one or two degrees below the probable freezing point of the liquid. The platinum wire stirrer S2 is then moved briskly up and down, when solidification will generally occur. The temperature indicated by T rises and shortly attains a value which remains constant some time. This temperature is the freezing point of the liquid.


Index of Instruments

Museum Home

Instrument Literature

 

 
HSTC (1921-34)
HSC (1935-1953)
HSC (1954-1973)
© R. Paselk
Last modified 22 July 2000