258 Dr. Daubeny on the Degree of Selection exercised by Plants, icith regcn-d 



phate of strontian, indicates how much is owing to the quantity of earthy 

 matter brought to it by the rains. 



The following is a tabular view of the results of the above-mentioned expe- 

 riments. 



In 1832 I made similar arrangements to those just alluded to, with the 

 addition of a fourth box, containing washed flowers of sulphur, and the omis- 

 .sion of those which the preceding year had remained in a garden. The four 

 boxes employed being placed in a greenhouse under cover, 300 grains of 

 barley were sown in each of them, and they were severally moistened, as they 

 seemed to require, with distilled water, containing in every ten gallons two 



