(9) 



The Main Conservatories. The contract of the Depart- 

 ment of Parks with John R. Sheehan for the building of 

 eight of the thirteen houses of the main range of Horticultural 

 Houses was completed in June and the buildings were at once 

 accepted by us for operation. Visitors have had access to 

 them everv day since their acceptance from 9 o'clock until 

 5, it not having been necessary to close them at any time. 

 Some difficulty was experienced at first in leakage in the roofs, 

 but this defect was remedied by Hitchings & Company, the 

 builders of the superstructure, and also by the operation of 

 the houses, the constant moisture from within acting to swell 

 the wood in which the glass is framed, so that the roofs 

 are at the present time essentially rain proof. A painter and 

 glazier was employed as soon as the buildings were accepted 

 and has been kept constantly at work in either external 

 or internal painting and in replacing such panes of glass as 

 have been cracked or broken from any cause. The trouble 

 from breakage has been very much less than was anticipated 

 considering the vast area of glass, and such as has occurred 

 seems to have been wholly caused by expansion or contrac- 

 tion, with the exception of one or two panes of glass broken 

 by solid objects blown against the roof in a very violent wind 

 storm during the autumn. An experience with a moderately 

 severe hail storm in the fall, was most satisfactory, the hail 

 stones glancing from the curved glass surfaces without fractur- 

 ing a single pane ; had the glass of the roofs been flat instead of 

 curved there is no doubt that considerable damage would have 

 been done. The heat-radiating surface of the steam pipes 

 within the houses has proved wholly adequate to yield any de- 

 sired temperature, at any external temperature yet experi- 

 enced ; in fact not more than one-half of it has been used at any 

 time ; the great palm house central to the system has proved 

 perhaps the easiest of all the houses to control. Some diffi- 

 culty was experienced in the early winter by a gaseous ema- 

 nation from the trench carrying the steam pipes longitudinally 

 under the houses ; the exact nature of this gas was not de- 

 termined ; the difficulty was remedied by ventilating the 



