PROPAGATOR. 



398 



PROPAGATOR. 



on ; and an under one, in which heat is 

 generated and applied. It will be under- 

 stood all the better if we take the simple 

 form . of a structure of this kind, which 

 any one may make for himself at the cost 

 of a few pence and a little thought and 

 contrivance. In the accompanying illus- 

 tration, in which this frame is illustrated 

 by means of a sectional diagram, the upper 

 or growing chamber, and the lower or 

 heating chamber, are recognisable at a 

 glance. The upper one consists of a 

 miniature frame easily made out of a box 

 to be bought of the grocer for 2d. or 

 3d., with the front lowered, the side cut 

 to slant from back to front, and a ledge 

 nailed round the top at A, A, A, so that 

 a plane of glass may be dropped into it. 

 The bottom is cut away, as shown at B, B, 

 so as to form another ledge projecting 

 inwards all round, on which a slate or a 

 sheet of metal is dropped, to form a false 

 bottom to the box. If it be asked, Why 

 take the trouble to cut out the wooden 

 bottom when, after all, a bottom is ab- 

 solutely necessary ? it is sufficient to say 

 that wood is a bad conductor of heat, and 

 slate or metal is a good conductor, and that 

 it is desirable to have the separating 

 medium between the upper and lower 

 chambers of material that is a good con- 

 ductor, so that the temperature of the air 

 in the upper chamber may be raised with 

 the least possible delay. Fill the bottom 

 of the receptacle thus made with cocoanut 

 fibre as far as the dotted line c, and nothing 

 remains but to put the seeds or cuttings in 

 small pots filled with light soil, and plunge 

 them in the cocoanut fibre. 



The next step is to procure a box, or 

 make a case, of exactly the same dimensions 

 within as the growing case is externally, 

 so that the latter may be dropped into it, 

 fitting with tolerable tightness ; ledges, 

 D, D, must be nailed to the interior of this 

 case all round, on which the upper box 



may rest. The front of the case may be 

 open from E to F to allow the lamp to be 

 taken out and put in at pleasure, and to be 

 visible at all times, so that the oil may 

 be replenished when it gets low. Now get 

 an Australian meat can, G, and having 

 removed the ragged top by cutting a nick 

 on one side with a file and putting it on 

 the hot plate of a stove to melt the solder, 

 put it in the centre of the case as shown, 



DIAGRAM ILLUSTRATING PRINCIPLE OF PROPA- 

 GATOR. 



letting the bottom fit tightly into a board 

 with a round hole cut in the middle of it 

 to take the tin, the bottom of which should 

 project beyond the lower surface to the 

 depth of about \ inch. This board, repre- 

 sented in section by EH, should be dropped 

 on to the ledges, D, D, and nailed to them 

 before the tin is put in its place. The 

 upper edge of the tin should rest on boards 

 contrived to slant from the top of the 

 ledges towards the tin, and for this reason 

 a tin that is square in form makes a better 

 boiler than a round one, because it is more 

 easily fixed. The junction between the 



