( 576 ) 
The apparatus consisted of two equal parts, i.e. of two semicircular 
tin-plate reservoirs with fixed bottom and loose lid. The two half¬ 
cylinders had on the middle of the flat side a portion which- was 
bent like a half cylinder, so that the two reservoirs when joined to 
form one cylinder, left in the centre a space for the passage of the 
trunk, which was to be cooled. The height of the apparatus was 
50 cm., its diameter 30 cm.; the space left free for the trunk had 
a diameter of 10 cm. Each reservoir was provided at the bottom 
with a tap, through which superfluous water could run off. The 
cylindrical surface of each reservoir and also the bottom and the lid, 
were covered on the outside with a layer of felt, 15 mm. thick and 
over this there was a covering of asbestos paper, 2 mm. thick. In an 
experiment the two reservoirs were placed round the stem and 
screwed together, after a piece of felt had been placed between the 
two flat surfaces in apposition. 
The reservoirs were filled with ice. The space through which 
the trunk passed, was closed off above and below round the stem 
by a solid plug of cotton wool through which a thermometer passed. 
The temperature in the annular air space surrounding the trunk 
varied between 0° and + 3° C. 
The apparatus w$s sufficiently protected by the felt and the asbestos 
against the heat of the surrounding atmosphere. Even on hot days 
it was only necessary to renew the ice twice in 24 hours. 
