THE ARTIFICIAL SEASONING OF TIMBER 



411 



instrument can be corrected from time to time to agree with the wet and 

 dry bulb thermometers. 



With an Erith or other progressive dryer, the recorder bulbs are 

 placed in the dryer near the hot end. The records should show either 

 two concentric circles in the case of a dial instrument, or two parallel 

 Unes with the drum type. 



There are, of course, unavoidable fluctuations due to opening of doors 



aOTH THERMOME.TERS 

 READING EQUAL 



ORV 



3Q_ 



BOTH PENS Oh 

 SAME LIME 



DRY Bum 



WET 



BULB ^ (M BULB 



THERMOMETERS READING EQUAL .OR RECORDER P£MS TQCETMER 

 INDICATES WET AIR IN KILM 



BIG OIFFEREMCE 

 BETWEEN TWO 

 THERMOMETERS 



PENS WlOt APART 



DRY BULB 



DRY ^ j^wtr 

 BULB m BULB 



BIG DIFFEREMCE BETWEEIJ THERMOMETERS OR RECORDER PEIJS 

 mOICATES DRY AIR IN KILN 



and the Uke, but for good working the wet and dry bulb readings should 

 be practically steady. 



With compartment dryers, where the temperature and humidity are 

 varied according to a predetermined course, the temperature line will 

 rise gradually from atmospheric temperature to full heat, and the wet 

 bulb hne wiU start close to the temperature Une (indicating great moisture), 

 and gradually fall away from it as drier air is used. 



The above diagrams show the analogy between the wet and dry bulb 

 thermometers, and the recorder, under extremes of wetness and dr3niess. 



