76 BEEHIVES AND BEE KEEPERS' APPLIANCES. 



The thickness of the frame should be If in. ii 

 the glass windows are fitted as shown by B (Figs. 

 69 to 71) ; but if the glass is to be fixed by a bead 

 or strips of wood against the frame A, an increased 



Fig. 70. Vertical Cross Section of Observatory Beehive. 



thickness will be necessary. The top and bottom 

 pieces of the inner frame are fastened at the 

 corners by screws or nails as shown in Fig. 73. The 

 notches in the side pieces are cut with a tenon saw 

 and a chisel to a depth of li in., just sufficient to 



