14 



UNIV. OF N. H. AGR. EXPERIMENT STATION [Bulletin 240 



Plate 2 — Shows (below) table with absorbers to collect carbon dioxide and water from [ 

 ventilating air current and meters for measuring the volume of ventilation. The long 

 glass aspirator tubes hung in a frame attached to the wall behind the right end of the table 

 are used to collect an aliquot sample of carbon dioxide free air for determination of marsh 

 gas. The manometers on the right above barometer indicate air pressure in chamber and 

 in the air sampling can. Above is same table with absorbers removed showing pump 

 operated by electro-magnetic device to collect an aliquot air sample from ventilating 

 current. 



