Aprils, 1885] 



NA TURE 



533 



change of colour and whether it is connected with any 

 special state of the weather I have not yet determined. 



Note. — Since the above was written, I have made a 

 rough attempt to measure definitely the rate of growth of 

 these crystals. A cylindrical stoneware bottle 36 inches 

 high and 2 '2 5 inches diameter was stuck upside down on 

 a post 40 inches high for three hours at a time, the crys- 

 tals formed on it melted down and the volume of the water 

 measured. Assuming that the cylinder acted like a flat 

 surface placed perpendicularly to the wind whose height 

 and breadth are equal to its height and diameter — an 

 assumption that appears to be very nearly true, at least 

 for small surfaces — I find that with dense fog and strong 

 wind (force 6 to S of Beaufort's scale) the rate of growth, 

 as measured above, is abouto'125 inch per hour. That is 

 to say, if the density of the snow be one-tenth that of the 

 water, the crystals were growing at the rate of one and a 

 quarter inch per hour. The crystals were quite loose 

 and feathery, and contained practically no fallen or 

 drifted snow ; all had been formed directly out of the 

 fog. R. T. OMOND 



BIRD ARCHITECTURE 



"p HE way in which a bird builds its nest, seemingly 

 * without instruction, thought, or experience, has been 

 repeatedly brought forward as a convincing proof of blind 

 infallible instinct governing it in its task. No more 

 popular proof has been brought forward by the supporters 

 of the blind instinct theory than that of bird-architecture. 

 It is thought a wonderful thing for a bird to build a nest 

 without any instruction, or without ever seeing a nest 

 typical of its species. That birds are capable of such 

 marvellous powers has long ago been denied by Mr. 

 Wallace, and we have not a particle of evidence that such 

 is really the case (" Nat. Selection," and Seebohm's 

 Brit. B.," ii. Introd.). Indeed the evidence, such as we 

 can glean, goes far to disprove the presence of any such 

 instinctive power. Birds brought up in confinement have 

 been found not to make a nest typical of their species, 

 but generally content themselves with forming a rudi- 

 mentary structure — heaping a lot of material together 

 without any design, or even laying their eggs on the bare 

 ground with no provision at all! In my opinion, how- 

 ever, the conditions of life are so changed when a bird is 

 kept in confinement that too much weight should not be 

 attached to its actions in captivity, and the experiment 

 has never to my knowledge fairly been tried with wild 

 birds or birds living under normal conditions. 



A remarkable instance, however, of a changed mode of 

 nest-building has just been brought to my notice by Mr. 

 W. Burton, the well-known naturalist of Wardour Street. 

 Some time ago his brother (now employed at the museum 

 at Wellington, N.Z.) took out to New Zealand a number 

 of young birds of our common native species, with the 

 object of introducing them to the Antipodes. Amongst 

 them were some young chaffinches {Fring'dla Calebs). 

 These were turned out and have thriven well in a 

 wild state, bidding fair to permanently establish this 

 charming little bird in our distant colonies. Some of the 

 birds have built a nest ; and to Mr. Burton I am indebted 

 for a photograph of the wonderful structure they have 

 woven. It is evidently built in the fork of a branch, and 

 shows very little of that neatness of fabrication for which 

 this bird is noted in England. The materials with which 

 it is made seem very different, too. The cup of the nest 

 is small, loosely put together, apparently lined with 

 feathers, and the walls of the structure are prolonged for 

 about eighteen inches, and hang loosely down the side of 

 the supporting branch. The whole structure bears some 

 resemblance to the nests of the Hangnests (Icteridae), with 

 the exception that the cavity containing the eggs is situ- 

 ated on the top. Clearly these New Zealand chaffinches 

 were at a loss for a design when fabricating their nest. 



They had no standard to work by, no nests of their own 

 kind to copy, no older birds to give them any instruction, 

 and the result is the abnormal structure I have just de- 

 scribed. Perhaps these chaffinchesimitated in some degree 

 the nest of some New Zealand species ; or it may be 

 that the few resemblances this extraordinary structure 

 presents to the typical nest of the Pakearctic chaffinch 

 are the results of memory — the dim remembrance of the 

 nest in which they had been reared, but which had almost 

 been effaced by novel surroundings and changed con- 

 ditions of life. Any way we have here, at last, a most 

 interesting and convincing proof that birds do not make 

 their nests by blind instinct, but by imitating the nest in 

 which they were reared, aided largely by rudimentary 

 reason and by memory. I have not the least doubt that, 

 had these young chaffinches been hatched in an alien nest 

 in this country, and never allowed to see a nest typical of 

 their species, or have any connection with old and expe- 

 rienced birds, the results would have been still more 

 startling and strange. Man has to learn the particular 

 art of house-building practised by his own peculiar race 

 — birds have to do the same ! Charles Dixon 



THE INSTITUTION OF NAVAL ARCHITECTS 

 THE Annual Meetings of the Institution of Naval 

 -*- Architects were held during the week preceding 

 Easter at the rooms of the Society of Arts. There were 

 five sittings, at which the necessary routine business was 

 transacted, the presidential address of Lord Ravensworth 

 was delivered, and seventeen papers were read and dis- 

 cussed. On the whole the meetings were successful and 

 the papers of good quality, but far too much work was 

 attempted in the time available. It is to be hoped that 

 the growing importance of the proceedings and the im- 

 proving financial position of the Institution may lead the 

 Executive to arrange for holding regular autumnal ses- 

 sions at the principal outports, in addition to the spring 

 sessions in London. 



The papers read were chiefly " papers of information," 

 having a strictly practical or descriptive character, only 

 two or three having scientific pretensions. Marine en- 

 gineering also occupied a far more prominent place than 

 has been usual hitherto, nearly one-half of the papers 

 having relation to the propelling apparatus of steamships. 

 The fact is significant, indicating the remarkable progress 

 which has recently been made in marine engineering, and 

 suggesting the progress which may yet be made. Of the 

 papers coming into this group, that by Mr. Macfarlane 

 Gray, of the Board of Trade, was the only one of a scien- 

 tific nature. Mr. Gray has on more than one occasion 

 brought his " ether-pressure " theory before the Physical 

 Society, where it has not been well received. His recent 

 paper " On the Theoretical Duty of Heat in the Steam- 

 Engine " was probably understood by only a few of his 

 hearers ; and Prof. Cotterill, whose authority on the sub- 

 ject is undoubted, was the only speaker who really con- 

 tributed any useful criticism. While complimenting Mr. 

 Gray on some of his graphic processes, and expressing 

 admiration for his courage and perseverance, Prof. Cot- 

 terill took exception to the generalisations attempted in 

 the paper and to the assumption that the results so far 

 obtained were any real confirmation of the soundness of 

 the theory advanced. 



All the other engineering papers were of a practical 

 character. The actual performances of " triple-expansion " 

 engines as compared with the " double-expansion " or 

 ordinary compound marine engines, were discussed at 

 length. Experience appears to be conclusive on the 

 point that, by using steam of 120 to 150 pounds' pressure, 

 and having three successive expansions in separate 

 cylinders, an economy of from 15 to 20 per cent, in coal 

 consumption is to be realised. This economy is of the 

 highest importance, both in mercantile and war ships 



