THE REGULATION OF TEMPERATURE. 



75 



of 6 or 8. The two smaller metal 

 doors of the larger bath are like the 

 corresponding doors in the smaller 

 bath, except that they are inserted in 

 a larger door, which serves as a frame. 

 The relations of the three doors will 

 be seen in Figures 44 and 45. The 

 largest door and the lower small one 

 are packed with hair and are opened 

 only when it is necessary to introduce 

 or remove apparatus, or to make some 

 adjustment of the instruments within. 

 The upper of the two smaller doors, 

 which must be opened whenever an 

 observation is to be made, is provided 

 with a device (Figure 43) for the inde- 

 pendent regulation of its temperature. 

 As regards the disposition of the space 

 between the glass and the metal doors, 

 there is no difference between the larger t F ! G : 43 

 baths and the smaller ones. 



Automatic arrangements for main- 

 taining temperature of upper door when open. 



G'.A55 IJOOIZ 



arqb // 2 Small DoohsW door 



m Larcset 



Doors. 



Fig. 44. — Larger (elliptical) bath for high temperatures. Horizontal section. 

 (C), (C), and (C) pumping tubes; (L), (L), (L) lamp compartments. 



No lamps of more than 16 candle-power are used in baths of Type IV, 

 even when they are maintaining temperatures near the boiling-point of 



