ON THE MERITS OF IRON AND WOOD FOR ROOFS. 51 



which was fifty feet long, fourteen wide, and fourteen high, with- 

 out any pit in the middle. 



Having thus stated the dimensions of the houses, I shall now 

 give the result of the investigation and calculations made relative 

 to fuel, attention, &c. &c. the coals for both houses were mea- 

 sured before being placed for use, and after the consumption of 

 the night's fuel, the result was as follows ; the iron roof with 

 18 degrees of frost, required the consumption of nearly six 

 bushels of coals, and unremitting attention during the night or 

 until 3 o'clock in the morning, while the house with the wooden 

 roof, consumed scarcely three bushels of fuel, in order to keep 

 it at the same degree of temperature with its iron rival, and no 

 attention was required after 10 or 11 o'clock at night, when the 

 fires were made up and left. Moreover, being determined to 

 investigate thoroughly the merits of the two materials, I caused 

 a house constructed of wood, and also one of iron, precisely the 

 same dimensions as regards superficial feet of glass, to be per- 

 fectly repaired in the autumn of 1832, and on having them ex- 

 amined and repaired in the following season, I found that in the 

 cost of repairing the iron house was nearly double the sum re- 

 quired to repair the wood : I do not mean to say that double the 

 number of squares were absolutely broken, but including the 

 broken and cracked squares, there was more than double the 

 number, destroyed, and this is attributed to the expansion of the 

 iron during summer, and its contraction in the winter. 



From these calculations it is evident wood has the advantage 

 over iron in four very essential points, viz. the saving of fuel, 

 glass, and labour, and in the better growth of plants and fruits, 

 as I have invariably found plants do not thrive so well nor look 

 so healthy in an iron as in a wood roofed house. The non-con- 

 ducting power of wood, and the electrical, nay, I may say, ca- 

 loric sensibilities of iron, may be the cause of this difference. 

 Iron is infinitely more liable than wood to the sudden and in- 

 jurious extremes of temperature from heat to cold. I have always 

 found during my practice, that no matter how the iron house is 

 situated, unless there was a slight shading on the houses during 

 the hot days in the summer months, the leaves of the pines and 

 other plants become very brown and frequently scalded ; but 

 whenever these shadings are not used, I would strongly re- 

 commend that a large cistern or trough of water should be placed 

 about the houses to make up for the continued evaporation for 



