GARDEN ARCHITECTURE. 
233 
construction of plant-houses. By not a few whose opinions are entitled to mucli 
respect, it is made to consist almost wholly in the primal outlay, or actual expense 
of erection ; no allowance being made for the comparative liability of certain 
methods to injury or decay, or to the varied amounts requisite to keep them in 
due repair. Clearly we pronounce such estimates of economy to be raised on a 
false foundation. 
But there is another and more prevalent species of error to which builders and 
even the great majority of culturists are prone in calculations of that sort. We 
allude to the very frequent forgetfulness that, since the houses are made for growing 
certain plants, and since the plants are the real property, which is simply to be 
conserved by their erection, that plan of building which most rapidly increases their 
beauty, and consequent value, will, in proportion to the benefits so conferred, com- 
pensate for the extra original expense. On the other hand, in estimating the cost 
of a structure, the worth of the specimens lost, and the additional value which 
the remaining plants would have acquired in a superior erection, ought fairly and 
undoubtedly to be added to the expenditure upon an unsuitable building, which 
was constructed for a lower price. 
After the above explanation, it will be superfluous to say more than that we 
include in all our calculations of expense, the ultimate effects of the plan pursued 
upon the final objects of care — the plants. Now, we maintain, from indisputable 
data — which any one may verify by personal experiment, or by visiting places in 
which exactly the same modes of cultivation are followed, but in houses of the two 
opposite classes to which we have pointed — that the improved health of the plants 
in greenhouses with two glass slopes to their roofs, is, in only three or four 
years, more than enough to repay the additional sum expended in their erection, 
supposing this were as great as the most extravagant economists affirm it to be. 
That it is really very trifling, or does not admit of proof, we proceed to demonstrate. 
Taking for our subject a span-roofed house of determinate dimensions, with 
either one or both ends glazed, and upright side sashes of from three to four feet in 
depth, all the latter adapted for opening, and the top lights capable of being let 
down or removed, we shall have a structure which, for appearance and for practi- 
cal purposes, cannot well be surpassed. Let us then imagine a lean-to house of 
the same length and breadth, with similar glazed extremities, and an equal depth 
of upright sash in front, (for few will have the hardihood to say that front and end 
lights can be dispensed with,) and it will be seen by measurement, that, on account 
of the greater height necessary in the latter, the length of slope in its roof, and the 
additional glass consumed at the ends, it will give quite sufficient to glaze the opposite 
slope of a span roof, while the expense of the back wall will surely allow for the 
remaining side iiglits of a span-roofed structure, and thus the cost of each is 
equalized, without reckoning how many more plants the one we recommend would 
accommodate. 
We hope, if our investigation has been tedious, it will not be deemed useless ; 
VOL. VIII. NO. XCIV. H H 
