364 
DARWINISM 
CHAP. 
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 7 00 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 
No. 
Species. 
Approximate 
No. of Seeds 
in one Grain. 
Approximate 
Dimensions. 
Remarks. 
1 
Draba verna 
1,800 
in. in. in. 
1 V 1 V 1 
uu x UU x TUT} 
Ovalj flat. 
2 
Hypericum perforatum 
520 
1 v 1 
UU x UU 
Cylindrical. 
I 3 
Astilbe rivularis. 
4,500 
1 v 1 
UU X TT}T) 
Elongate, flat, tailed, wavy. 
4 
Saxifraga coriophylla . 
750 
1 v 1 
477 A 7 5 
Surface rough, adhere to the 
5 
(Enothera rosea . 
640 
1 v 1 
T77 x ■§'77 
dry capsules. 
Ovate. 
6 
Hypericum hirsutum . 
700 
1 v 1 
UU x T7777 
Cylindrical, rough. 
7 
Mimulus luteus . 
2,900 
1 v T 
7577 x T777J 
Oval, minute. 
8 
Penthorum sedoides . 
8,000* 
1 V 1 
775 x T317 
Flattened, very minute. 
9 
Sagina procumbens 
12,000* 
1 
T7T77 
Sub-triangular, flat. 
10 
Orchis maculata 
15,000* 
Margined, flat, very minute. 
11 
Gentiana purpurea 
35 
TU 
Wavy, rough, with this cori- 
12 
Silene alpina 
TV 
aceous margins. 
Flat, with fringed margins. 
13 
Adenophora communis 
^77 x ¥77 
Very thin, wavy, light. 
Quartz grains 
25,000 
l 
TUT} 
Deep sea . . 700 miles. 
Do. 
200,000 
l 
T7777 
Genoa . . . 600 miles. 
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. 1 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 
1 I am indebted to Professor R. Meldola of the Finsbury Technical Institute, 
and Rev. T. D. Titmas of Charterhouse for furnishing me with the weights 
required. 
