MOISTURE CONDENSATION ON GLASS WOOL 



L91 



Figure 19 shows the apparatus. The tube A contains distilled 

 ■water freed from air. B is a chamber between stopcocks to con- 

 tain a small amount of water from A. C is another chamber 

 between stopcocks, the "feed chamber." A mercury manometer, 

 D. is for the purpose of reading pressures inside the apparatus. 

 E is the bulb containing the glass wool. The tube marked "to 

 pump and gauge" was sealed off following the drying process 

 and before any water feeds were let into the apparatus. 



The method of feeding was to saturate the feed chamber with 

 water vapor, and then open this chamber into the apparatus, the 

 stopcock between it and chamber B having first been closed. In 

 Trouton's apparatus the feed was made from a capillary cham- 

 ber (with a similar arrangement of stopcocks) filled with water 

 in the liquid state. Thus the amount of water let in at any one 

 feed was much greater than in the modified method, and Trouion 

 could get only two or three separate feeds into his apparatus 

 before the phenomenon of pressure drop occurred. Likewise in 

 the part of the curve immediately following this drop only a 

 general notion of what was actually taking place could be ob- 

 tained because of the few readings in this region. 



Fig. 20. 



Trouton's method of drying was to immerse the wool chamber 

 in hot oil kept at the desired temperature as Long as the drying 

 continued. In the present work an electric oven served, without 



