GKOWTH OF PLANTS IN THE PURE EARTHS. 57 



to full liglit and dry aii' for a length of time, the tissue will 

 become harder than if the leaves were grown in comparative 

 darkness. We need no stronger proof of this than the acrid 

 flavour of the outer as compared with the inner leaves of the 

 same celery, a fact demonstrating that if the leaves are exposed 

 for a long time they acquire an acrid flavour which no blanching 

 can wholly remove. 



For an early croj) of celery I sow in heat early in January, 

 and prick the plants out upon a slight hot-bed ; for a second 

 crop in February in heat as before directed, and for a late crop 

 in March in the open garden. 



[Note. — This communication accompanied some very fine red 

 celery, to which a Certificate was awarded.] 



X. — Experiments on the Growth of Plants in the Pure Earths, 

 and also with Stimulants and Manure, made in the Years 

 1843-44. By W. H. Pepys, F.K.S., F.H.S. 



(Communicated February 18, 1845.) 



T'l T^ .1 f Silex . . . . 75 "I White Sand, 

 ihe Earths I * i • i r ti- i 



, j ^ < Alumine . . . 15 > Fipe-clay. 



" ^ ( Carbonate of Lime 10 J Whitening. 



100 



The pots in which the experiments were made were green 

 wine-bottles, cutting off their bottoms and reversing them on a 

 stand for that purpose. (See figure, in next page.) 



April 26th, 1843. — The first experiment consisted in mixing 

 the earths in the proportions desciiljed, and having placed some 

 broken green glass as crocks in the gla.ss pot.-;, they were nearly 

 filled with the mixed earths. Three yellow lupine-seeds, each 

 weighing 2^\ grains, were then planted about half an inch deep 

 therein, and watered with 3 oz. 5 drams of distilled water and 

 exposed to the atmosphere. They were watered every day until 

 the 29th of May, with from half an ounce to an ounce of dis- 

 tilled water; anci on that day one of the seeds broke ground, 

 only the cotyledon making its appearance ; the watering- was 

 continued, and on the 5th of June a small plume appeared, but 

 very weak, which increased but very slowly. On tiie 10th of July 

 tlie plant had six leaf-stalks, of six leaves each ; and on the 

 1st of August, the plant being very weak, with eleven leaf- 

 stalks, and no sign of bloom, it was removed from the vessel, 



