40 



HORTICLLILRAL APPLIANCES AT THE PARIS EXPOSITIOA. 



1. The upper ridge must have sufficient slope to carry 

 off the condensed vapor, not through capillary attrac- 

 tion, but by means of the weight of the liquid. 



2. The frame-work must be outside, in order to 

 avoid the vapor on the interior, and it should extend 

 to the ground, upon which it should rest. 



3. The glass in the Dutch houses must be joined end 

 to end at the ridge, where condensation takes place. 



4. The glazing should be made with free joints, 

 without tringles, for these only increase the expense 

 and are of no use. Double glazing should only be re- 

 sorted to when strictly necessary, for the expense is 

 heavy and cleaning the glass very difficult. With us 

 the cold is not so intense as to require its use. 



5. Lateral ventilation must be given through open- 

 ings under the walls, so that the air first strikes the 

 heated pipes ; and the ventilation above must be so 

 arranged that it will in no way injure the plants. 



6. The screens will always furnish better shade if 

 they can be unrolled six or eight inches above the glass. 

 This may be done by having them rest upon a frame. 



7. It is always a good plan to have double doors at 

 the entrance. 



Of the greenhouses exhibited, that of M. Izambert 

 appeared to possess all the modern improvements. It 

 was well-planned, solid, light and quite cheap. M. 

 Cochn exhibited a greenhouse having the frame of 

 wood. This showed that our builders can do as well as 

 the Belgians or English in the use of pitch pine, which 

 growers prefer. 



We continue to make the slat screens of narrow 

 pitch pine. These are fastened together by rings of 

 wire, only a narrow space being left between them. 



The appliances and structures scattered about the 

 Trocadero served the purpose of four exhibitions, for 

 there were the greenhouses proper, appliances for 

 heating them, various fixtures and the plants which 

 various horticulturists had brought. One could hardly 

 notice anything but the marked improvements which 

 have been made in hot-beds. The number of these 

 now in use is enormous, and they are heated by regular 

 hot-water systems instead of by manure, as formerly. 



The round greenhouse of G. Sohier was a work of 

 art rising above the others. It united the conditions 

 of taste, solidity and lightness. M. Sohier is also the 

 builder of the large Brazilian greenhouse on the Champ- 

 de-Mars. 



I must also mention here the greenhouses which had 

 the ends of boards. These fitted in the iron frame 

 and could be removed when necessary. The price of 

 espaliers is also much lower, so that they can easily be 

 used for fruit trees and vines. 



Quite a number of kiosques werealso exhibited in the 

 Trocadero, some having simple, and others rustic trel- 

 lises. Japan had a small bamboo house, of little im- 

 portance. It was much smaller than the one at the Ex- 

 position of 1878. Two builders, Messrs. Simard and 

 Prunieres, had erected rustic pavilions. These were 

 built of wood, bark and colored plaster. The most re- 



markable exhibit of this kind was a Swiss cottage, ex- 

 ceedingly well arranged. It was placed at the service 

 of the committee on horticulture. 



INSECTICIDES AND ATOMIZERS. 



The number of manufactures of insecticides grows 

 every day ; each one calls himself a chemist and pre- 

 tends, or believes, to have discovered some new combi- 

 nation. The question of insecticides is becoming to be 

 of the highest importance, for in proportion as we im- 

 prove our fruits, the plants seem to be attacked by new 

 diseases and enemies, to which our fathers seemed to 

 pay no attention. It often occurs that a large part, or 

 even the whole of a crop is lost on account of the at- 

 tacks of some animal or vegetable parasite. 



One should always prefer those insecticides which 

 contain fertilizing elements, such as potash, sulphur 

 and lime. For the mealy bug {Schizoneura lanigera), 

 which is the pest of our orchards, not less than one 

 hundred methods of extermination are given, all more 

 or less effective ; only one thing is lacking, and that is 

 a quick and easy method of application. Besides the 

 three substances mentioned above, there are two others 

 which are very important, viz. petroleum, diluted with 

 water for the destruction of caterpillars, and tobacco 

 juice for use in the greenhouse. At first tobacco smoke 

 was used, but this was found to be injurious to delicate 

 plants, then pulverized tobacco was used, but the pow- 

 der did not always reach the under side of the foliage, 

 where the insects laid their eggs. During the last few 

 years we have employed an effective method, one which 

 has not the objectionable features of the two just men- 

 tioned ; it does not injure the plants, and the insecti- 

 cide penetrates everywhere. It is the vapor of the 

 juice of tobacco ; this is obtained in various ways, either 

 _ by throwing the liquid on hot bricks placed upon the 

 soil ; or by special furnaces, placed outside of the 

 greenhouse, the fumes entering the house through open- 

 ings made for the purpose. In the United States, wag- 

 ons are used for working in an orchard. They carry 

 portable tents which are spread over the diseased tree, 

 and a fumigating apparatus supplies the tent with the 

 vapor. Many of our horticulturists employ bi-sulphide 

 of carbon for the destruction of white grubs. It is put 

 in vessels, and used in the same manner as in the 

 vineyard. 



In conclusion I will say that only in details could one 

 see improvements on the exhibits of the Expositions of 

 1867 and 1878. There were lacking the foreign exhibits, 

 for comparison ; the locations furnished by the admin- 

 istration were not as favorable as might have been de- 

 sired ; and finally, the attractions of the Champs-de- 

 Mars and of the Invalides were such that every visitor 

 eagerly hastened to them. But the true admirer, far 

 from the noise of the kiosques and the restaurants, found 

 in the Trocadero endless pleasure in the marvelous 

 collections of plants which were exhibited, and which 

 for a long time to come will not again appear in this 

 admirable situation. 



