THE WEIGHT AHD GEEMINATION TEST. 149 



water will enter by capillarity through its sides, but principally by 

 way of the hole in the bottom through the layer of coarse sand or 

 broken tiles^ 



For soil may be substituted sawdust, pounded charcoal or coke 

 or brick-dust, especially if the seeds are small or are Hkely to suf- 

 fer from being clogged over too thickly with mud. All four sub- 

 stances are highly absorbent, admit air freely, and, while retaining 

 moisture well, yield it up slowly but with sufficient rapidity for the 

 requirements of germination. Moreover charcoal and coke are 

 natural preservatives against decomposition. 



There is, however, no necessity in every case for burying the seed 

 at all. Some seeds, such as those of bamboos and many leguminous 

 kinds, germinate easily and rapidly enough if simply kept in a warm 

 place in a shallow dish of water. Others sprout if simply enclosed in 

 a roll of some loose-woven woollen cloth, such as flannel, that is con- 

 stantly kept moist. The best way to keep the cloth moist, without al- 

 lowing it to become too wet, is to connect it by means of a sufficiently 

 thick skein of wool or worsted with water standing at a lower level 

 than itself, so that the quantity ascending by capillarity may just ex- 

 ceed the quantity lost by evaporation. If, owing to rapid evaporation, 

 especially in a dry atmosphere, the woollen cloth is hkely to cool 

 down too much, it may be put under a globe of glass or metal, and, if 

 necessary, exposed thus to the sun or before a fire. But a still 

 better plan (see Fig. 5) is to use a wide-mouthed glass bottle, 

 which is kept partly filled with water. One end of the skein being 

 hooked on to the mouth of the bottle, the other is allowed to hang 

 down in the water as far as the bottom itself, while the roll of 

 woollen cloth containing the seeds is attached to the skein above 

 the level of the water. In order to check evaporation and the 

 consequent refrigeration, a perforated cork or wooden stopper or 

 tin-cap should be put over the mouth of the bottle. The water 

 can be replenished whenever necessary. The bottle, with its skein, 

 stopper and roll of woollen cloth, thus forms an easily-portable 

 apparatus, which can be exposed to the sun or before a fire, or kept 

 in a warm place, just as is required, and maybe carried about 

 on long journeys without interfering with the trustworthiness of 

 the test. The glass jars, with screw tin-caps, in which prunes are 

 imported to India, will serve the above purpose excellently. 



Various special apparatus have been contrived for procuring the 

 germination of seeds under the most favourable conditions irres- 

 pective of the season of the year. Two of these may be here de- 

 scribed. 



