272 THE ORCUID REVIEW. 
the nitrate of potash. This worked put at the rate of 2°5 grains per gallon. 
Many of the flowers of the Cattleya which were shown at the Drill Hall on 
May 9gth this year were larger, brighter, and had more substance than in 
previous years. 
This year I intend to increase the amount to 5 grains per gallon during 
the summer, that is to say, from May to September. I also propose to ~ 
treat some of the plants with small quantities of phosphate of ammonia 
and carbonate of magnesia, in addition to the nitrate of ammonia and 
potash. I expect that I shall be able to make a favourable report on a 
future occasion on the results of these experiments. 
Orchids take up through their leaves carbonic acid, free ammonia, and 
water in the form of watery vapour, but I believe the alkalies and earthy 
salts are taken up through the roots. It is probable that many of the 
Orchids which grow, in their native habitats derive their earthy salts from 
the bark of the trees on which they grow, by a process of dialysing the 
earthy salts from the tree and absorbing them through the root of the 
Orchid. I have found that hanging an Epidendrum ciliare up and simply 
watering, although it flowered for the first year or two, ultimately perished, 
no doubt due to exhaustion caused by the removal of a certain proportion 
of the earthy salts by the flowers, and by the inability of the plant to obtain 
a fresh supply of the earthy salts. Dendrobium nobile will also exist for a 
year or two under similar conditions, but will gradually decrease in the size 
of its growth, and ultimately perish. 
I suspect that phosphates increase the inflorescence of plants. Last 
year I watered a Marechal Niel rose in a pot with water containing nitrate 
of ammonia. Although the plant made a strong growth of 10 feet in length, 
the flowers were very few in number this year, and badly developed; on the 
other hand, two Gloire de Dijon roses, which I fed with phosphate of 
ammonia in addition to the nitrate, had in the one case 93 and in the other 
over 180 large and fully-expanded blooms open at the same time. 
In concluding this letter, I cannot help expressing a hope that the 
Horticultural Society or Amateur Orchid Growers will raise a fund to be 
expended in having a thorough analysis made by a professional chemist of 
the chemical constitution of Orchids, together with the mineral and alkaline 
salts of the flowers, and pseudobulbs of the principal species of Orchids, 
which are in cultivation at different seasons of their growth. I feel 
convinced that many obscure points in their habits would be cleared up and 
a more rational treatment would follow, in place of the empiric and rule of 
thumb method of cultivation now in vogue. 
The Grange, 
Carshalton, 
A, H. SMEE, 
