HARDWICKE'S SCIENCE-GOSSIP. 



237 



formauce in the "Philosophical Transactions" for 

 1788, and this] has been recently confirmed by a 

 letter in Nature on the 14th of May, 1872, by J. B., 

 author of " Caw, Caw," who witnessed the transac- 

 tion. This has been still further confirmed by Mr. 

 John Hancock, of Newcastle, who says, "On the 

 6th of June, 1S64, I observed a nest of the Hedge 

 Accentor, which contained five eggs, four belonging 

 to this bird and one to the cuckoo. I visited the 

 nest again on the Sth of June, and found three 

 young accentors and the cuckoo hatched, one of 

 the hedge accentor's eggs having disappeared ; the 

 three young hedge accentors lay on one side of the 

 nest, the other, the cuckoo, by itself. On the morn- 

 ing of the following day, I once more went to the 

 nest ; the three accentors were gone, and the 

 cuckoo was the sole occupant. One of the accent- 

 ors lay dead on the ground below the nest. On the 

 10th of June I saw the foster parents feeding the 

 cuckoo." — Dipt on Burn. 



Cuckoos and their Eggs.— Mr. Copeman will 

 find, on further investigation, that Dr. J. E. Taylor's 

 account of the various colour of cuckoos' eggs, 

 given in his most interesting "Half-hours in the 

 Green Lanes," is home out by other naturalists of 

 high repute. If he will tuni to Chambers's Journal 

 for May, he will there meet with the following para- 

 graph : — " In 1853 Dr. Baldamus, of Stuttgart, 

 published a series of interesting observations on the 

 egg-lajing peculiarities of this singular bird. He 

 attempts to prove, and with considerable success, 

 that the egg of the cuckoo agrees in colour with 

 those amongst which it is placed. That she can 

 voluntarily influence the colour of her eggs. He 

 enumerates the nests of thirty-seven species — to 

 which list the editor of the Ibis has added fifteen — 

 frequented by the cuckoo. There is certainly a very 

 marked resemblance in many instances between the 

 egg of the cuckoo and those of the species whose 

 nest is selected, though there are notable exceptions, 

 such as that, of the hedge-sparrow, whose blue-green 

 eggs bear no resemblance to the colour of any egg 

 laid by the cuckoo. In this case, however, it may 

 be that the hedge-sparrow is one of those species 

 more easily duped than others, so that the deception 

 of colour is not necessary." — James Rogers, Bolton. 



Cuckoos' Eggs.— Mr. Copeman will find an 

 article in Science-Gossip for May, 1870, written 

 by Mr. J. E. Harting, on the cuckoo, in which Mr. 

 Harting refers to a discovery by Dr. Baldamus, that 

 hen cuckoos are endowed with the faculty of laying 

 eggs similar in colour to those of the species in 

 whose nests she lays, in order that they may be less 

 detected by the foster-parents. This is corrobora- 

 tive of the statement made by Mr. Taylor in his 

 " Half-hours in the Green Lanes."— R. Christie. 



How to destroy Clothes-Moths.— In reply 

 to the query of W. Benn in a recent number, I beg 

 to recommend him the following plan for the de- 

 struction of the larvae of moths infesting woollen 

 goods. Take a coarse towel or cloth, and wet it 

 thoroughly ; fold it to three or four thicknesses, and 

 lay it on the part suspected, and pass over it a very 

 hot iron. The steam generated kills the larvse and 

 cooks the eggs. I have tried it on a couch and 

 carpet that were much infested with entire success, 

 and have not found it damage either the carpet or 

 the green wool rep cover of the couch.—/. S. L. 



Decay of Trees. — Some remarks in Science- 

 Gossip for August call attention to the decay of 



trees in Hyde Park, and it is stated there how the 

 leaves and fruits of these trees have been carefully 

 swept away from year to year without substituting 

 any manures in their place. What suicidal policy ! 

 for by this means the very food of the plant has 

 been taken away from it. It might have occurred 

 to some one before that each tree must naturally 

 drain up all the available nutrition in a given area 

 if no more were added, and that supplied by nature 

 were persistently swept away as it fell. As an 

 evidence of how much nutrition there is in the 

 decaying leaves, &c, I will quote the tables of 

 Professor Wolff, and give a few of his analyses. 

 Eirst, then, in "fruits and seeds of trees " :— 



Also the following leaves 



It is obvious from these tables what a constant 

 supply of nutritious material there is in fallen leaves 

 and fruits, which are as beneficial as a manure ; for 

 these decaying and liberating their salts, which 

 become dissolved in the water of the soil, become 

 a constant source of nutrition for the plant. So 

 that whether in the form of raphides or sphse- 

 raphides (as Science-Gossip says), it does not 

 matter very much, whether as double phosphates of 

 calcium and magnesium (as in globoids), or as 

 calcium carbonate (as in cystoliths), still the ulti- 

 mate analysis of the leaves shows us how much real 

 food there is contained in them, and how essential 

 it is to allow them to decay on the ground, or else 

 supply their place by suitable manure. We have 

 only need tojpoint to the luxuriant vegetation found 

 in woods where the leaves are thick on the ground 

 as a proof of this. Every one of your readers will 

 have some recollection of a beautiful, damp, moist 

 glen or dell, inches thick in decaying and decayed 

 leaves, and in which cryptogamic vegetation is 

 luxuriant, and the large trees are always green and 

 healthy ; and evidently this is because Nature sup- 

 plies her own manure, and the broom of civilization 

 is not there to sweep it away, and make clean at 

 the expense of life. I may add that these tables 

 are quoted from Professor Johnson's "How Crops 

 Grow."— R. N. W. 



Density of Sea Water. — Perhaps some of 

 your readers can enlighten me in regard to the 

 following: in Professor (now Sir) Wyville Thom- 

 son's "Depths of the Sea," on page 304 is the 

 following statement :—" It has been shown by 



