PLATE XXXIV 



Fig. I. — Balance for weighing oxygen cylinder and end view of absorber table: 



A, Cylinder containing oxygen under pressure; B, empty cylinder for counterpoise; 

 C, valve for reducing pressure of oxygen from cylinder ; D, rubber bag to collect sample 

 of air for determination of residual oxygen; E, meter for measuring sample of air for 

 determination of residual moisture and carbon dioxid; F, pipe for air returning to 

 chamber; G, pipe for air coming from chamber; H, valve for closing circulating air 

 system between absorbers and ingoing air pipe; /, trap for removal of sulphuric-acid 

 spray from retviming air; K, point at which air from meter is restored to air returning 

 to chamber. 



Fig. 2. — Method of attaching heating and cooling systems to zinc wall: A, Hooks of 

 iron wire, screwed into metal framework, supporting brass pipe for cooling zinc wall; 



B, porcelain insulators, carrjnng resistance wire for heating zinc wall; C, exterior ends 

 of wooden supports of thermoelements projecting from zinc wall; D, wooden strip, 

 dividing air space adjacent to zinc side walls into upper and lower zones. 



