ON THE CULTIVATION OF THE PERSIAN VARIETIES OF THE MELON. 



air of the house. Air is admitted through apertures in the front wall, 

 which are four inches wide, and nearly three in height ; and which are 

 situated level with the top of the flues, and are eighteen inches distant 

 from each other. The air escapes through similar apertures near the top 

 of the back wall. These apertures are left open, or partially or wholly 

 closed, as circumstances require. Thirty-two pots are placed upon the 

 flues described above, each being sixteen inches wide at least, and four- 

 teen inches deep ; but they are raised by an intervening piece of stone 

 and brick out of actual contact with the flues. Into each of these pots 

 one melon plant is put, which in its subsequent growth is trained upon a 

 trellis placed about fourteen inches distant from the glass, and each 

 plant is permitted to bear one melon only. Each might be made to bear 

 more, but if they should be as large as Ispahan melons are when perfect, 

 they would certainly be of inferior quality. The height from the ground 

 at which the trellis is placed is such that I can with convenience walk 

 under it, and of course discover without difficulty the first appearance of 

 red spiders, or other noxious insects. 



When I left the country to come to London in the last spring, my 

 plants were growing most luxuriantly ; and their appearance was every- 

 thing that I wished. But during my absence a few red spiders 

 appeared upon one of the plants, as I had anticipated, and my gardener, 

 in consequence, and in obedience to my instructions, sprinkled the under 

 surfaces of the leaves frequently, and rather freely, with water. By these 

 measures the increase and spreading of the red spider was effectually 

 prevented ; but on my return from London, I found that my plants had 

 wholly ceased to grow, though their appearance was healthy ; and subse- 

 quently all the fruit dropped off* either before or soon after their blossom 

 had expanded. I in consequence immediately ordered other plants to be 

 raised, still, however, entertaining hopes of preserving those I had. But 

 those hopes were not realised ; and I was obliged to throw away the 

 whole of them, with the exception of one, which was more healthy than 

 the others, and which lived to produce the first fruit sent to the Society. 

 That appeared to be, as it proved, of good quality ; but it was defective 

 in size ; its weight seemed little, if anything, more than five pounds. 



My second family of plants were treated nearly as the first had been, 

 and with the same approaching results ; but I was led by the discoveries 

 of M. Dutrochet to change my mode of management, and, I believe, to 

 discover the cause of the preceding failure. This eminent physiologist 

 had discovered that if a lighter fluid be in contact with one side of an 

 animal or vegetable membrane, and a denser fluid with the opposite side, 



