Retrospective Criticism, 275 



diiFerence would arise from the mode of setting the boilers, as I have heard 

 of some cases where very indifferent success has attended the use of them, 

 and which, as far as I could learn, has arisen from unskilful setting. To 

 judge from the remarks in your Magazine, it would appear that the practical 

 application of hot water is about to undergo a complete " revolution." I 

 was in hopes that the pubhc opinion on such matters had become more 

 settled, and that the notions which led so many astray, viz., that a penny- 

 worth of fuel would give more heat than a chaldron of coals, were now 

 quite repudiated ; and really, seeing the errors which have been heretofore 

 committed on this subject, I would caution ail persons against laying aside 

 inventions of tried and acknowledged excellence, for every new-fangled 

 theory which happens to be propounded. 



I am perfectly unprejudiced towards any plan and I should therefore be glad 

 to have any errors pointed out into which I may have fallen ; but, unlil this be 

 done, I prefer adhering to those plans which 1 know succeed perfectly, in 

 preference to adopting problematical and even fanciful advantages. — William 

 Andei'son. Brixton Hill, April, 1840. 



The Grand Conservatory at Chatsworth. — I quite agree with Mr. Forsyth in 

 his strictures on this structure (p. 103.), and on the ridge-and-furrow method 

 of roofing and glazing. If it be an improvement to consume more glass, more 

 wood, more paint, to subject the woodwork and putty to a better chance of 

 decay, to afford a good berth for a heavy fall of snow, why then it is per- 

 fection ; but not otherwise. The greatest improvement that I know of in 

 hot-house building is, glazing with lead instead of putty, and consequently 

 only exposing the sides of the sash-bars to the weather. — Amicus. Feb. 6. 1840. 



Habits of the Jackdaw. — I have lately read some of Mr. Waterton's articles 

 on ornithology, and have been much interested by the admirable manner of 

 his writing, though I cannot pretend to much acquaintance with such subjects. 

 It would be well if other writers on subjects of natural history, and especially 

 on botany, would imitate the simple natural style of Mr. Waterton, which 

 renders such essays infinitely more entertaining, than the rigid adherence to 

 scientific and technical terms and forms of expression. Among his many 

 interesting descriptions of various birds, Mr. Waterton has given a delightful 

 account of the peculiar habits of the jackdaw. He calls our attention to 

 what appears a great want of sagacity in this bird ; the fact of his many vain 

 attempts to introduce his sticks into the hollow where he begins his nest. 

 " You may see the jackdaw," he says, " trying, for a quarter of an hour, to get 

 a stick into the hole ; while every attempt will be futile, because, the bird 

 having laid hold of it by the middle, it is necessarily thrown at right angles 

 with the body, and the jackdaw cannot possibly perceive that the stick ought 

 to be nearly parallel with its body, before it can be conveyed into the hole." 

 Against this charge of defective knowledge in the jackdaw, it is my present 

 object to defend him to a certain extent. Like the rook, the jackdaw begins 

 his nest with pretty strong sticks; these he lays hold of by the middle, obviously 

 because he can thus support their weight best in his flight. It often happens 

 that the hole into which he tries to introduce the stick is small, while there 

 is no branch near it for him to perch upon, for the purpose of altering the 

 direction of his stick. He tries again and again to get the stick into the 

 hollow, and, if it does not either bend or break, he must let the stick fall, and 

 abandon his purpose, since he cannot use his claws in the hole to alter the 

 position of the stick. Those who have seen the jackdaw begin his nest in a 

 chimney, would give him credit for ingenuity in carrying his sticks horizontally ; 

 for this enables him to drop them down in the only way in which they could 

 become fixed for his purpose ; and in no place does he make so complete a 

 nest, as in a chimney. Mr. Waterton had recourse to a very ingenious ex- 

 pedient to induce his rooks and jackdaws to build on the same tree. He 

 made a cavity in an old elm tree, and a ptur of jackdaws took possession of 

 it, while the rooks built on the top of the same tree. I knew of an instance 

 at the seat of the Earl of Leven, Melville House, Fifeshire, where both these 



