meters from the top. A glass suction tube (with inside diameter 

 about 4 mm., is to be placed vertically against the wall of the 

 crock, its lower end resting on bottom of crock and its upper end 

 extending about 1 cm. above the rim. This tube is to be placed 

 before sand is poured into crock and will be held in position by 

 the sand. The lower end of the tube is to be loosely plugged with 

 glass-wool and tufts of the wool are to extend one or two centi- 

 meters beyond the tube, so that sand may rest on these and thus 

 hold the plug in place. 



A supply orifice is furnished by a paraffined paper cone (or a 

 100-cc. wide-mouth bottle with the bottom removed) , standing 

 at the center of the sand surface and embedded in it to a depth 

 of about two centimeters. The paper cone should be about six 

 centimeters high, four centimeters in diameter at its larger 

 (lower) end and two centimeters in diameter at its smaller 

 (upper) end. These cones are rolled from heavy paper, fastened 

 by a pin or paper-clip, and are heavily paraffined. 



Record the total weight of crock, tube, cone and sand. Cone 

 is not permanently placed till after seedlings are in position. 



The Seedlings. The seeds are to be soaked in germination 

 solution and allowed to germinate on the germination net, just 

 * as for water-cultures, the shoots being four centimeters high 

 when transplanting occurs. Selection is made just as for water- 

 cultures. It is of course desirable that all seedlings be as nearly 

 alike as possible. 



Introduction of Seedlings. When seedlings are ready, some 

 nutrient solution is poured on to the sand, to moisten it (a liter 

 of solution should be ready, but only a little is used at the start) , 

 the surface is levelled and the selected seedlings are introduced, 

 five in each crock. These are to be selected beforehand, as in the 

 case of water-cultures. They are planted so that the grains will 

 lie about one-half centimeter below the sand surface, equally 

 spaced, in a circle half-way between the supply cone and the wall 

 of the crock. A flat wooden dibble (like a spatula) about fifteen 

 millimeters wide and having a sharp edge is convenient for set- 

 ting the seedlings. (An ordinary pot label with broad end 

 thinned serves will.) Care should be exercised not to injure the 

 roots. 



The supply cone is introduced in the center of the sand sur- 

 face after the seedlings are in place, its larger end downward 

 and embedded in the sand to a depth of about two centimeters. 

 Then nutrient solution is poured in through the cone until the 

 liquid surface is about one centimeter above the sand, and the 



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