OF SEED-SOWING. 167 



Mag., xiv. 74) ; and it is stated that the results were 

 exceedingly striking. Old Spruce Fir seed, which 

 would scarcely germinate at two years old, produced 

 a fine healthy crop when three years old, having been 

 first damped and then mixed with newly slacked 

 lime; and, under the same treatment, an average 

 crop of healthy plants was obtained when the seed 

 was four years old. Unfortunately, the manner in 

 which the original experiments upon acids and alka- 

 lies were conducted is not explained, (it is to be 

 presumed that the water employed was only acidu- 

 lated with the acids spoken of,) and I am not aware 

 of the experiments having been repeated. — The last 

 method of promoting germination, to which it is 

 necessary to advert, is the mixing seeds with agents 

 that have the power of liberating oxygen. It has been 

 shown (14) that a seed cannot germinate until the car- 

 bon with which, it is loaded is to a considerable extent 

 removed ; the removal of this principle: is effected by 

 converting it into carbonic acid, for which purpose 

 a. large supply of oxygen is required. Under ordi- 

 nary circumstances, the oxygen is furnished by the 

 decomposition' of water by the vital forces of the 

 seed ; but, when those forces are languid, it has been 

 proposed to supply oxygen by some other means. 

 Humboldt employed a dilute solution of chlorine, 

 which has a powerful tendency to decompose water 

 and set oxygen at liberty, and, it is said, with great 

 success. Oxalic acid has also been used for the same 

 purpose. . 

 Mr. Otto, of Berlin, states that he employs oxalic 



