44 



THE NURSERY-BOOK. 



plate or disc, c c, is fitted. Above this is a glass top, Pp. Air is 

 admitted to the apparatus at i, PC K, and between the vase and 

 plate, as at c on the right. The plate contains two circular 

 grooves, g g and // h. In these grooves the soil is placed or pots 

 plunged. The heat circulates in the valleys m and n n n n, and 

 supplies a uniform temperature to both sides of the plants. 



Barnard's propagating-tank, Fig. 39, is a practicable device for 

 attachment to a common stove. A similar apparatus may be 

 attached to the pipes of a greenhouse. The tank consists of a 



Fig. 39. Barnard's Propagating-tank. 



long wooden box made of 

 matched boards, and put to- 

 gether with paint between the 

 joints to make the box water- 

 tight. The box should be about 

 three feet wide and ten inches 

 deep, and may be from ten to 

 thirty feet long, according to 

 the space required. In the 

 middle of the box is a parti- 

 tion, extending nearly the 



whole length of the box, and on the inside, on each side, is a 

 ledge or piece of moulding to support slates to be laid over the 

 entire surface of the box. The slates are supported by the 

 ledges and by the central partition, and should be fastened down 

 with cement to prevent the propagating sand from falling into 

 the tank. One slate is left out near the end, next the fire, to 

 enable the operator to see the water and to keep it at the right 

 lev^l. On the slates sand is spread, in which the cuttings may 

 be struck, the sand nearly filling the box. At one end of the 

 box is placed a common cylinder stove, with pipe to the chim- 

 ney. Inside the stove is a lead or iron pipe (iron is the best) 

 bent in a spiral. This coil, which is directly in the fire, is con- 



