HORTICULTURAL SOCIETY OF LON'UON. 



263 



the plants were washed clean, to remove all tlie soil in which 

 they had been growing, and were then potted in silver sand. 

 By this means they would depend chiefly for nourishment upon 

 the substances dissolved in the water, and it would then be seen 

 whether these of themselves were suHicient for their support. 



The salts were carbonate of ammonia, subcarbonate of am- 

 monia, sal ammoniac, common salt, saltpetre, nitrate of soda, 

 and carbonate of ammonia mixed with wood ashes. About two 

 tea-spoons full of salt to each gallon of rain-water was the 

 strength of each solution. The plants were then divided into 

 sets of three each, which were watered with the different salts 

 whenever the sand was dry. 



Other two sets of Pelargoniums planted in sand in the same 

 manner as the others, were watered with rain-water mixed with 

 the ammoniacal liquor of the gas-works in the proportion of 

 about half a pint to a gallon. In one of the sets the liquor was 

 used fresh from the cask, in the other it had been exposed for 

 some time to the action of the air. 



The result of these trials seems to be, that none of these 

 substances of themselves wuU support plants of this kind in a 

 healthy condition. Carbonate of ammonia with wood-ashes was 

 the most beneficial, and the subcarbonate, the carbonate, and 

 common salt did not seem to produce any bad effects, as the 

 plants here grew as well as some which were watered with pure 

 rain water. The remainder of the salts and the two kinds of 

 ammoniacal liquor were certainly injurious. 



Three plants of the same kind were potted in burnt clay, three 

 in pounded bricks and three in charcoal, and all were watered 

 with pure rain-water. In these circumstances they grew better 

 than any of the others, except those in the carbonate of ammo- 

 nia and wood ashes ; the two first, however, succeeding better 

 than the last which was in charcoal ; but none of them did so 

 well as some others which were in common garden soil. These 

 results were evidently for want of sufficient nourishment, in so 

 far as the burnt clay and powdered bricks were concerned ; the 

 charcoal might produce other effects, but other experiments are 

 still going on with this substance. 



I have also been trying what effects would be produced upon 

 Pelargoniums growing in common soil by watering them with 

 carbonate of ammonia, nitrate of soda, and Glauber's salts dis- 

 solved in rain-water. The proportions of the salts were rather" 

 greater than in the first instance. Each plant which was watered 

 with the salt, was placed by the side of another of the same 

 variety which was watered with pure rain-water. The difference 

 between the plants watered with the salt in solution and the 

 others was very apparent, the former being shorter jointed. 



