HYGROSCOPICITY 



.65 



III. VARIABLE SEEDS. (Hygroscopicity variable.) 



(Variable seeds are those where some are permeable and others impermeable, the pro- 

 portions being very inconstant, so that the hygroscopic range for different seed-samples 

 would vary much, and could only be characterised as intermediate between that for im- 

 permeable seeds (nil) and that for permeable seeds (2 to 4 per cent.). 



From the results of the observations on the hygroscopicity of 

 a number of seeds which are given above it may be inferred 



(1) That permeable seeds under ordinary weather conditions General 



vary to the extent of 2 or 3 per cent, of their weight drawn S from 

 in the course of two weeks, though the range may *^ e auth r 's 

 be reduced to I per cent, in equable conditions, and 

 increased to 4 or 5 per cent, when the weather is 

 characterised by extreme changes ; 



(2) That impermeable seeds have practically no hygroscopic 



reaction, such small changes as do occur, as of I in 

 1000 or of i in 10,000 of the weight, being either 

 instrumental or connected with loose tissue adhering 

 to the scar or to the raphe ; 



