3Q0 PROPAGATION OF THE SPECIES. CHAP. IX* 



water ; but to exclude all such small seeds as might 

 be wafted on the winds : the result was that no 

 plant came up.* 



In the summer of 1811, I had an opportunity of 

 making some similar experiments on earth obtained 

 from a considerable depth by the digging of a well 

 at Purleigh, near Maldon, in the county of Essex. 

 On the 15th of April I exposed a lump of this 

 earth, being chiefly a black clay taken from the 

 depth of 100 feet, to the action of the air and 

 weather, and to the operation of such other contin- 

 gencies as might occur : it was placed upon a slate 

 in one of the quarters of my garden. On the lOth 

 of May I placed another lump taken from the depth 

 of 150 feet upon a slate also, but under a hand-glass, 

 which was removed only to give it an occasional 

 watering. No symptoms of vegetation appeared in 

 either the one or the other till the 3d of September 

 following, when several plants were found in a state 

 of protruding their seed leaves from the surface of the 

 exposed clay, and one also from the surface of the in- 

 sulated clay; the former proved afterwards to be plants 

 of Senecio vulgar is, or Common Groundsel, which 

 was now coming up from seed all over the garden, and 

 hence easily accounted for : the latter proved to be 

 a plant of Ranunculus sceleratus, the seed of which 

 was undoubtedly brought to the clay along with 

 the water it was watered with, which came from a 

 pond at no great distance, round the edges of which 

 * Anat. Plant. Pars Altera, p. 92. 



