364 



DARWINISM 



pared with the enormous areas of sea-bottom, over which the 

 atmospheric dust must have been scattered, render it in the 

 highest degree improbable that the maximum limit either of 

 size of particles, or of distance from land has been reached. 



Let us, however, assume that the quartz grains, found by 

 Mr. Murray in the deep-sea ooze 700 miles from land, give us 

 the extreme limit of the power of the atmosphere as a carrier 

 of solid particles, and let us compare with these the weights 

 of some seeds. From a small collection of the seeds of thirty 



species of herbaceous plants sent me from Kew, those in the 

 above table were selected, and small portions of eight of 

 them carefully weighed in a chemical balance.^ By counting 

 these portions I was able to estimate the number of seeds 

 weighing one grain. The three very minute species, whose 

 numbers are marked with an asterisk ('"), were estimated by 

 the comparison of their sizes with those of the smaller weighed 

 seeds. 



If now we compare the seeds with the quartz grains, we 



^ I am indebted to Professor R. Meldola of the Finsbury Technical Institute, 

 and Rev. T. D. Titmas of Charterhouse for furnishing me with tlie weights 

 required. 



