348 VITALITY OF SEEDS — ITS DURATION. 



very stiff soils should be fifteen feet apart, and in very light soils 

 thirty or forty ; the depth being from thirty to thirty-six inches, and 

 the main drains six inches deeper than the parallel ones. In extremely 

 stiff clays he makes drains two and a half feet deep. He was the 

 first to advocate the system of parallel drains, or what is called 

 thorough-draining. 



Vitality op Seeds. — Some seeds lose their vitality soon, others 

 retain it for a long time. Coffee seeds, in order to grow, require to 

 be sown immediately after ripening. On the other hand. Melon seeds 

 have been known to retain their vitality for upwards of forty years, 

 and those of the Sensitive plant for more than sixty years. Oily seeds 

 in general lose their vitality quickly, probably from their power of ab- 

 sorbing oxygen, and the chemical changes thus induced. Considerable 

 discussions have taken place as to the length of time during which 

 seeds wiU retain their germinating powers. Lindley mentions a case 

 in which yoimg plants were raised from seeds found "in an ancient 

 barrow in Devonshire, along with some coins of the Emperor Hadrian ; 

 and M. des Moulins relates an instance of seeds capable of germinating, 

 which were discovered in a Eoman tomb, supposed to be fifteen or 

 sixteen centuries old. In these instances, it is to be remarked that 

 the seeds were protected from the influences required for growth, and 

 were preserved in circumstances which cannot be easily imitated. The 

 statements relative to the germination of Mummy Wheat, that is to 

 say, grain actually deposited in the case along with the mummy, have 

 not been confirmed, and there are many sources of fallacy. 



With the view of preserving seeds, it is of importance that they 

 should be thoroughly ripened, kept in a uniform temperature, and in a 

 dry state, and not directly exposed to the oxygen of the air. They 

 are often best kept in their seed-vessels. The hard coverings of many 

 foreign legumes,' and of the cones of Firs, etc., seem to be of importance 

 in preserving the germinating power of seeds. Seeds not fully ripened 

 are very apt to decay, and are easily affected by moisture. Seeds, 

 although fit for food, may have lost their germinating power. Com, 

 pulse, and farinaceous seeds generally, will live for a long time if 

 gathered ripe, and preserved quite dry. In sending seeds from foreign 

 countries; they should be put up into dry papers and exposed to free 

 ventilation in a cool place ; as, for instance, in a coarse bag suspended 

 in a cabin. Oily seeds, and] those containing much tannin, as beech- 

 m£ist, acorns, and nuts, must not only be ripe and dry, but also must 

 be excluded from the air. When transported they are often put into 

 dry eaith and sand, and pressed hard, the whole being covered with 

 tin, and put into a stout box. Some have suggested their preservation 

 in hermetically-sealed bottles full of carbonic acid gas. Earthenware 

 bottles, containing ordinary soil, moderately dry, are useful for the con- 

 veyance of seeds. A common wooden box, about 10 inches square, with 



