368 



Retrosjiective Criticism. 



house. Most kinds of cookery might also be effected by gas ; and what 

 could not, would only require a little coke or charcoal. 1 he gas lights ot 

 churches and other public buildings might, in many cases, communicate heat 

 as well as light, simply by having a double spiral funnel {fig. 131.) over tne 

 flame, and a going tube (a), a returning tube (b), 

 and a pressure or balance tube {c c), communi- 

 cating with a reservoir; which reservoir might 

 either be under the floor or in any part of the 

 house between the floor and the roof. But per- 

 haps the best way of heating churches would be 

 to have two or three solar concentrators on the 

 roof, communicating with an immense cistern 

 under the floor. There would at least be enough 

 of sunshine during the week to produce heat for 

 Sundays. The immersion tanks of Baptist cha- 

 pels might be heated in this way, the water of 

 public and private baths, and the mode is applic- 

 able to a variety of other cases. The only ques- 

 tion is, as to the expense of the concentrators, 

 and the machinery requisite to keep them conti- 

 nually at the proper angle to the sun's rays. We 

 wish some person of leisure, ingenuity, and a 

 little spare money, would communicate with Mr. 

 Gauen on this subject, and determine a number of 

 points by experiment. To heat by concentrators 

 a vault of water under a pit, either for protecting plants during winter, 

 or for early forcing, would be one of the easiest and most desirable objects 

 to begin with. 



Art. VIII. Retrospective Criticism. 



Position of Cottages. — Sir, Observing the liberal candour with which you 

 correct your opinions, if your correspondents adduce reasons which appear 

 to you better than your own, I venture to offer some remarks on passages 

 in your Magazine for July, 1827. In p. 478- (of Vol. III.) on Cottage Eco- 

 nomy, you require that a north and south line should form a diagonal to 

 the square of the outer walls. Now, admitting your position that both the 

 sun and wind striking obliquely will fall on the walls with moderated force, 

 I totally deny your conclusions. You seem to assume that the wind will 

 always blow from the four cardinal points; but, in this climate at least, the 

 fact is otherwise; and when it does blow from either of the four cardinal 

 points, the wind is less, and therefore its direct impulse is desirable. For 

 instance, a south wind is always a soft and pleasant wind, so, for the most 

 part, the west wind ; the north wind is dry, wholesome, and, though cold, 

 not injurious or unpleasant. In praise of the east wind, indeed, I can only 

 say, that it is dry, and not very prevalent. Now, if these winds come with 

 their full force direct on the walls of a house, not much harm is done, and 

 much pleasure and benefit result ; but, if you change each front 45 degrees, 

 you have indeed one front direct to receive the delicious south-easter, the 

 opener of flowers, and morning's whet to trouts and salmons ; but, against 

 that, you have the next front fully exposed to the south-wester, bringing 

 five sixths of all the rain that falls, and ninety-nine hundredths of all the 

 driving rains, to wet through all the walls that art can construct, at least in 



