THE CONSTRUCTION OF PLANT HOUSES. 97 



Reference being made to the house with a short slope to the 

 south, Mr. Burn ham said it was a good house for some purposes, 

 as it admitted a good deal of light to plants which could be grown 

 near to the glass ; but during the prevalence of snow and ice, it 

 might remain covered by them a week or more at a time, which 

 was an important drawback from its usefulness. It has been 

 recommended for forcing vineries, but has no advantages for this 

 purpose. The best form of house for grapes is the full span, with 

 curvilinear sides, ridge running north and south. This form 

 utilizes the sunlight from the rising to the setting of the sun, as 

 some portion of the glass is always at the proper angle for that 

 effect. A house of this style, but running east and west, was built 

 for the late William Astor ; the south side for forcing, the north side 

 for retarding the maturing of the grapes. Into the latter portion 

 very little direct sunshine penetrated, and the crop of fruit ripened 

 at about the holiday season. The borders, when frozen, were 

 covered so as to keep the vines from starting until about June 1st. 



In answer to a question as to the preferable size of glass for 

 greenhouses, Mr. Burnham stated that the general opinion among 

 florists would favor sixteen by twenty-four inches. The larger 

 sizes come into what the trade call "the next bracket" and cost 

 about two cents per foot extra. Glass fourteen to sixteen inches 

 wide, by sixteen to twenty-four inches long is preferable to larger 

 sizes, making the tightest glazing and involving the least cost for 

 repairs. If the larger glass is used, the sash bars must be 

 increased in depth. The careful glazier will assort glass into 

 three grades, as straight, curved, and much curved, and set the 

 lights which are alike together, thus avoiding openings at the laps. 



Mr. Appletou asked whether there would not be trouble with 

 vermin in a house where iron posts were used. Mr. Burnham 

 answered that, as compared with a solid masonry foundation, 

 there might be some objection to the posts on this account, but it 

 would not be fatal to their use ; in the past most florists' houses 

 have been built on wooden posts without serious trouble from 

 vermin. As compared with a dry stone wall below grade, as 

 frequently used, where vermin could harbor for the winter, the 

 iron posts would be decidedly preferable. 



The President announced for the next Saturday a paper on 

 " Mushrooms," by William Falconer, Glen Cove, N. Y. 



7 



