Jan. 30, 1879] 



NATURE 



291 



British ornithologists — Yarrell, Macgillivray, Gould, Meyer, and 

 Morris — describe the eye of the Golden Eagle (the less rare of 

 our two British species, and the on£ usually referred to by our 

 poets) as hazel or brown. The eye of the Sea Eagle is described 

 by the same authorities as yellow. I cannot think that so accu- 

 rate an observer of nature as Shakespeare would call either 

 hazel or yellow eyes green. Can Mr. Ingleby cite any authority 

 for such a comparison as ' ' green as is an eagle's eye " ? while 

 the keen piercing sight of the bird is as proverbial as the swiftness 

 of its flight. I am well aware that green eyes were held in high 

 estimation by the old poets, especially by those of Spain ; Shake- 

 speare, however, does not seem to me to have shared in this pre- 

 dilection, as, setting aside the doubtful play of " The Two Noble 

 Kinsmen," and the pa-^sage now in question, he uses the epithet 

 three times only, I think, as applied to the eye, and then 

 always in nialavi farlem, viz., "green-eyed jealousy," "Mer- 

 chant of Venice," Act iii. Sc 2 ; "It is the green-eyed monster," 

 '* Othello," Act iii. Sc 3 ; and in " Midsummer Night's- Dream, ' 

 Act v. Sc, 2, where the " eyes as green as leeks ' are met with in 

 conjunction with " lily lips," "cherry nose," and " yellow cow- 

 slip cheeks." I cannot think with Mr. Murphy (Nature, 

 vol. xix. p. 197), that the eyes which the old poets so admired 

 as green were what we call blue ; they were more probably ^0'> 

 which often has a shade of green in it — the " even grey as glas "' 

 of Chaucer's "Prioresse." These green or grey eyes were, I 

 think, usually an attribute of feminine rather than masculine 

 beauty, as in the passage from "The Two Noble Kinsmen," 

 Act V. Sc. I, where they are mentioned in an address to Diana 

 (not Neptune, as Mr. Ingleby has it). Shakespeare well distin- 

 guished between the different colours of eyes — see " Two Gentle- 

 men of Verona," Act iv. Sc. 4, and " Twelfth Night," Act i. 

 Sc. 5, for grey eyes ; "As You Like it," Act iii. Sc. 2 for blue 

 eyes ; " Romeo and Juliet," Act ii. Sc. 4 for black and grey eyes, 

 and Act iii. Sc. i. of the same play, where hazel eyes are 

 mentioned. Robert Brewin 



Exeter, January 20 



Intellect in Brutes 



Sir Harry Lumsdkn allows me to publish the following 

 little incident : — Late last autumn some partridges, which he had 

 tamed and kept about the house, disappeared as usual and 

 became wild. When the excessive cold set in and Aberdeen- 

 shire was deep in snow, Sir H. Lumsden was greatly pleased 

 and surprised one morning to find his old friends on the door- 

 step waiting to be fed. Next morning they appeared with a 

 wild covey of eleven birds, and the tame cock sat on the door- 

 step and crowed to the wild birds, evidently encouraging them 

 to come and eat the food, which, however, they declined to do 

 till it was put further from the house. Soon after the tame birds 

 appeared with two covies. How did they entice the wild birds 

 except by actual bird talk ? 'Walter Severn 



Feeding a Python 



The attack of a constrictor, at all events in confinement, is 

 very often unsuccessful ; but perhaps this may be because the 

 reptile is not hungry. I have often seen the constrictors in the 

 London Zoological Gardens strike several times at birds, pulling 

 out feathers and even getting a firm hold and then releasing their 

 prey, to renew the attack presently either with or without 

 success. When the membrane over the eye is becoming opaque 

 in consequence of the change of skin they frequently fail to hit 

 the prey at all, but still persist until they secure it. I saw one 

 of the large pythons take a rabbit in a way which must be 

 unusual, I think. The rabbit was hopping about near the snake's 

 coils when the reptile suddenly made a loop in its body, and firmly 

 inclosed the victim without touching it at all with the mouth, or 

 even raising its head. The rabbit died there, but the snake paid no 

 attention to it for a quarter of an hour and subsequently swallowed 

 it very leisurely. Arthur Nicols 



THE GRAHAM LECTURE, ON MOLECULAR 

 MOBILITY 



'T'HIS lecture, the institution of which was referred to 



■*• in Nature, vol. xix. p. 254, was delivered on the 



22nd inst., by Mr. W. Chandler Roberts, F.R.S., Chemist 



of the Mint, before the Philosophical Society of Glasgow, 



in the hall of the University, where Graham graduated in 

 1824. 



The audience, which was very large, included most of 

 the professors of the University. 



Mr. James Mactear, president of the Chemical Section, 

 pointed out that they were doubly fortunate in ha\-ing 

 secured the services of Mr. Roberts, whose co-operation 

 in his work Graham repeatedly acknowledged in the 

 warmest terms, and in the fact that Mr. James Young, 

 F.R.S., of Kelly, the life-long friend of Graham, had con- 

 sented to preside on this occasion ; he therefore vacated 

 the chair in favour of Mr, Young, who introduced the 

 lecturer. 



Mr. Roberts briefly traced the influence of Black and 

 Thomson in turning the attention of Graham to the study 

 of molecular physics, to which he patiently devoted his 

 life. In connection with the law of the diffusion of gases 

 the lecturer claimed that Priestley made in 1799 an ob- 

 servation on the escape of hydrogen from a cracked jar. 

 The subsequent and independent discovery of this phe- 

 nomenon by Doebereiner in 1823 has hitherto been con- 

 sidered the starting-point of the experimental study of 

 gaseous diffusion to which it undoubtedly attracted Gra- 

 ham' s attention. After a brief review of the influence of 

 Eastern and Greek thought on the study of molecular 

 movement, allusion was made to Sir Christopher Wren's 

 model representing the effects of all sorts of impulses that 

 result from the impact of hard globulous bodies, which, 

 according to Dr. Sprat, historian of the Royal Society, 

 he proposed as the principles of all demonstrations in 

 natiural philosophy, it being considered " that generation, 

 corruption, and all the vicissitudes of nature are nothing 

 else but the effects arising from the meeting of little 

 bodies, of different figures, magnitudes, and velocities." 



Herepath's revival of Bernoulli's view as to the 

 movement of gaseous particles was considered, and Mr. 

 Roberts then described in detail the experiments that 

 enabled Graham to establish the law of the diffusion of 

 gases, and he illustrated experimentally the passages of 

 gases through porous bodies, such as unglazed earthen- 

 ware and artificial graphite, as well as through a layer of 

 the hard translucent variety of opal known as hydrophane. 

 The mode in which Graham studied the diffusion of the 

 momentum of gases, by observations on viscosity as indi- 

 cated by rates of flow through capillary tubes, was then 

 described. It was pointed out that his law of diffusion 

 forms the basis of the science of molecular mechanics, 

 and his measurements of the rates of diffusion prove to 

 be the measure of molecular velocities which have been 

 so profoundly investigated mathematically by Clerk- 

 Maxwell, Clausius, and Boltzmann, and experimentally 

 by Loschmidt in developing the dynamical theory of 

 gases. The lecturer then considered the passage of 

 gases through colloid or jelly-like bodies which have no 

 sensible pores, dwelling more especially on the separation 

 of oxygen from air by the transmission of air through a 

 thin filni of india-rubber, a circumstance of special inte- 

 rest from a physiological point of view. 



The liquefaction of gases formed the subject of one of 

 Graham's earUest papers, in 1826, and it occupied his 

 attention at intervals during his life. He held the view 

 that hydrogen w^hen absorbed by palladium is reduced to 

 the metallic form, a supposition which has received strong 

 confirmation from the success that has attended M, Raoul 

 Pictet's efforts to solidify this gas ; and that distuiguished 

 physicist stated in a letter to i^Ir. Roberts that it is 

 probable Graham's indication of the density of solid 

 hydrogen will prove to be nearly correct. Allusion was 

 then made to Graham' s opinion that the various kinds 

 of matter now recognised as different elementary sub- 

 stances may possess one and the same ultimate or atomic 

 molecule existing in different conditions of movement, 

 thevarving degrees of rapidity of this movement consti- 

 tuting, "in fact, the difference between the elementary 



