124 MODERN BEEHIVES. [Ch. hi. 



stopped, when necessary, by a zinc slide passing down 

 between. The octagonal cover b is about ten inches in 

 diameter and twenty high, including the sloping octa- 

 gonal roof, surmounted with an acorn as a finish. There 

 are two large windows in each of the end boxes and one 

 in the centre box. Across the latter is a thermometer, 

 scaled and marked, so as to be an easy guide to the 

 bee-master, showing him, by the rise in temperature, 

 the increased accommodation required ; this thermometer 

 is a fixture, the indicating part being protected by two 

 pieces of glass, to prevent the bees from coming between 

 it and the window, and thereby obstructing the view. 



D D are ventilators. In the centre of each of the end 

 boxes is a double zinc tube, reaching down a little below 

 the middle : the outer tube is a casing of plain zinc, with 

 holes, about a quarter of an inch wide, dispersed over it ; 

 the inside one is of perforated zinc, with openings so 

 small as to prevent the escape of the bees ; a flange or 

 rim keeps the tubes suspended through a hole made to 

 receive it. The object in having double tubing is to 

 allow the inner one to be drawn up, and the perforations 

 to be opened by pricking out the wax, or rather the 

 propolis, with which bees close all openings in their 

 hives. These tubes admit of a thermometer, enclosed 

 in a cylindrical glass, being occasionally inserted during 

 the gathering season ; it requires to be left in the tube 

 for about a quarter of an hour, and on its withdrawal, if 

 found indicating ninety degrees or more, ventilation must 



