March 20, 1902] 



NATURE 



465 



the mere conversion of fuel energy into mechanical work is not 

 the most important function, and the machine is very complex. 

 Still, in it we have no heat engine, but the sort of thing we are 

 looking for. I do not wish to set capitalists and patent lawyers 

 against me, and so I will not give my reasons for saying that 

 there is no sufficient temptation for any scientific man to take 

 up the quest. Unless it is taken up as a matter generally 

 recognised to be of national or world-wide importance, there is 

 no more use in tackling the problem than in hunting De Wet 

 with a small army. Many scientific men must combine their 

 efforts in an organised way, freely communicating their ideas to 

 one another and consulting each other as to their experiments. 

 They must be made free from pecuniary cares and assured of 

 great rewards in case of success. I feel sure that if one or two 

 chiefs like Lord Kelvin or Lord Rayleigh were entrusted with 

 the expenditure of a million a year for two or three years by the 

 English nation for the benefit of the world, with power to 

 impress the services of all scientific workers likely to be of use, 

 to make their operations as extended as they pleased, they would 

 bring the invention within reach of the ordinary engineer. 



John Perrt. 



Birds attacking ButterfJies and Moths. 



It was inevitable that the question of birds attacking butter- 

 flies would lead to some account of their attacks upon moths. 

 Although I do not believe that any doubt has been thrown upon 

 the keenness and frequency of the pursuit of moths by birds, a 

 few examples of unusual interest deserve permanent record. 



About the year 1887 I saw a fine specimen of the Lobster 

 Moth (Stauropits fagi) at rest on the lamp-post at the entrance 

 to Norham Gardens, Oxford. So far as I was aware, it was 

 the first specimen which had been noticed in Oxford, and I was 

 anxious to secure it. The moth was gently touched by a stick 

 tied to an umbrella and came fluttering down feebly towards 

 the ground, when, as I ran to catch it, a sparrow dashed across 

 and seized it before it had reached the ground. I chased the 

 sparrow, encumbered with the heavy moth, for some distance, 

 and at first thought it would relinquish the prize. But it soon 

 flew up to the roof of a house and ate the moth in the rain-water 

 gutter. 



I am indebted for the second and very remarkable example 

 to Mr. W. Eagle Clarke, of the Edinburgh Museum of Science 

 and Art. He writes, March i : — " I send you an account of 

 what I think is a somewhat unusual instance. 



"In June last, as I was walking at midday along the road 

 which runs close to the shore of Loch Assynt, in north-west 

 Sutherland, a male Oak Eggar Moth [L. querciis) dashed past 

 me with the swift irregular flight characteristic of that species. 

 Suddenly a wheatear, a male, gave chase and, after several 

 failures at capture, succeeded, after a clever but trying pursuit, 

 in securing its prey. The body, &c. , of the moth was eaten on 

 the road, where I found the wings, the only remains. 



" If I had not seen this ' flight ' from start to finish, I should 

 not have thought it possible that a wheatear could have been so 

 swift and smart on the wing, for, as you know, an Oak Eggar is 

 not an easy quarry to secure when in flight. 



" I have seen a great titmouse capture the white butterfly — 

 Pteris rapae — on the wing." 



I am sure that any naturalist who is familiar with the flight 

 of the male Oak Eggar will feel all the astonishment which Mr. 

 Clarke expresses at the success of the bird. 



The two remaining examples deal with attacks upon the pup.-e 

 of moths. 



In July, 1900, Mr. A. H. Hamm, of the Hope Department, 

 showed me a number of cocoons of the Lackey Moth (C. 

 Neiistria), which had just been opened, probably by sparrows, 

 and the pup^ extracted. 



The cocoon is tolerably dense, and is probably still further 

 protected by an abundant sulphur-coloured powder which 

 consists of minute crystals of aragonite (calcium carbonate), 

 secreted by the malpighian tubercles of the larva and extruded 

 from the anus before pupation. The cocoons were spun upon 

 the under sides of leaves of black currant and apple, and it was 

 of the highest interest to observe that every one had been 

 opened by the bird pecking a hole in the leaf from the upper side 



NO. 1690, VOL. 65] 



and thus making an aperture in by far the thinnest part of the 

 cocoon. The observation was made in Mr. Hamm's garden in 

 St. Mary's Road, Cowley Road, Oxford. 



The last example is equally interesting, but does not deal 

 with the attacks of birds. 



Colonel J. W. Yerbury informs me that when collecting on 

 Beown Mountain, Macgillicuddy Reeks, Kerry, on July 21-22, 

 1 901, he found under a stone, at the height of more than 2000 feet, 

 the old winter store of a mouse or possibly a shrew, consisting 

 of eight to ten cocoons of the Emperor Moth (Sattiinia carpini). 

 Every cocoon had been gnawed through at the base, viz. the 

 end opposite to that from which the moth emerges, and the 

 pupa extracted. Edward B. Poulton. 



Oxford, March 6. 



Sun Pillars. 



On Thursday the 6lh inst. a very fine display of this 

 phenomenon was observed over a considerable area in the west 

 of England, and having regard to Prof. Herschel's interesting 

 letter on the same subject published in Nature on July 4 last 

 (No. 1653, vol. Ixiv. p. 232), perhaps the few facts I have been 

 able to collect may be of interest to some of your readers. 



For several days the weather had been exceedingly fine and 

 dry, with hot sunshine and a wind following the sun. The wind 

 on the evening in question had almost died away at sunset ; the 

 latter was at 5h. 46m. Greenwich time, and would be about 

 6h. 5m. here. Close upon 5h. 30m. the light-beam first appeared 

 rising vertically from the sun, which was still visible above a violet- 

 coloured bank of haze ; its base did not extend below the sun. 



The beam had the appearance of a tall column of very beautiful 

 orange-coloured light brighter in the centre than at the edges ; its 

 top must have been quite 20° above the horizon. The sun sank 

 into the haze about 5(1. 45m. ; the column remained just as bright 

 though reddening gradually until 6h. 20m., and was still dis- 

 tinctly visible at 6h. 40m. It had faded away by 6h. 50m. 

 Faint bands of cloud were visible round the sun, and these 

 sloped from the top of the light-column obliquely downwards in 

 a northerly direction ; I .also noticed a repetition of the beam on 

 either side of it, though this may have been purely an optical 

 illusion. 



I have ascertained that the effect was seen over the whole of 

 Cornwall and Devon, as far east as Salisbury and Taunton, 

 and north as far as Pendine in Carmarthen Bay. Snow has not 

 fallen here for several weeks. W. H. Graham. 



Fowey, March II. 



In reply to Mr. Knight's inquiry in last week's Nature 

 (P- 439). he may be referred to many old books, as, for instance, 

 to Moigno's " Repertoire d'Optique Moderne," published in 

 1847, in the first volume of which he will find a whole section 

 devoted to meteorological optics. The explanation of most of 



