Moisture Content of iSorne Typical Goals. 



177 



very thin walled tubing (-3 mm.) and fitted the heating- 

 tube of the apparatus very exactly so as to insure a good 

 heat conductivity. Attached to the bucket is an alumin- 

 ium wire which carried two disks of aluminium which 

 served to prevent convection currents. The convection 

 currents due to a temperature of 250° to 300° in the 

 heating tube with — 78° in the insert tube, cause excessive 



Fig. 2. 



Fig. 3. 



Fig. 4. 



D 



A 



H 



LA 



/^ 





Fig. 2. — I, insert tube. L, insert tube and container for weighing. 

 K, coal bucket. N, N, aluminium disks. 



Fig. 3. — A, constant boiling liquid. B, electric heater. C, condenser. 



Fig. 4. — D, air or gas inlet. G, concentrated H,S0 4 . H, connection with 

 apparatus fig. 2. 



convection currents even with small gas pressures and 

 it was found best to avoid them and in fact necessary 

 when the volume of the gas was to be measured. The 

 disks had a diameter of about one millimeter less than 

 that of the tube. The partial pressure of the water 

 vapor in the apparatus was kept very low during the 

 heating by condensation on the lower part of the insert 



