122 



NATURE 



[NOVFMBER 24, 1 9 10 



iiCIENCE AND ENGINEERING. 

 A T a meeting of the Junior Institution of Engineers on 

 ■^ November 15, Sir J. J. Tliomson, F.R.S., president 

 of the association, delivered an address on the relations 

 between, pure science and engineering. The distinction 

 between them, he said, is one of airn, not of method. 

 The methods employed by the physicist and the qualities 

 of mind called into play in his investigations are to a 

 large extent the same as those used by the engineer in 

 the higher branches of engineering. It is not the business 

 of the physicist in his researches to concern himself at all 

 with utility. Almost every advance in pure physics has 

 been turned to account by the engineer, the manufacturer, 

 or the doctor. But nothing would be more disastrous to 

 the progress of engineering than that the workers in pure 

 .science should hamper themselves by considerations as to 

 the utilitv of their work, or confine their attention to 

 points which have an obvious practical application. 



The province of engineering is to survey the facts known 

 to science, and to select those which seem to have in them 

 the possibilities of industrial application, and then to study 

 and develop them from this point of view. This can often 

 best be done in laboratories attached to works engaged 

 in active trade. The success of works' laboratories in 

 Germany and the United States, and to a growing extent 

 in this country, is one of the most striking features in 

 modern industrial development. A closer connection with 

 pure science would be of the greatest service to engineer- 

 ing and commerce in this country, and though strides 

 have been m.-ide in this direction in recent years, Sir J. J. 

 Thomson pointed out we are still behind Germany in the 

 importance we attach to pure science and in the eager- 

 ness with which new discoveries are applied to industrial 

 purposes. As an instance, to judge from the number of 

 " Thermos flasks " met with, the manufacture of these 

 flasks must constitute a large and profitable business. It 

 is sard, however, that none of these flasks is made in 

 England. Yet the Thermos flask is an English invention, 

 being nothing but what is known to physicists as the 

 " Dewar vessel," which was invented by Sir James Devvar 

 for the purpose of storing liquid air without evaporation, 

 and was described by him some years ago. Although the 

 discovery was made and first published in England, no 

 English manufacturer took it up, but left it to foreign 

 rivals to make it the basis of an important trade. 



It is, he continued, the object of applied science to keep 

 theory and practice at the same level. Theory and practice 

 do better work when they are driven abreast rather than in 

 tandem. The more intimate the relation between the. 

 workers in pure science and those engaged. in the applica- 

 tion of science, the greater will be the opportunities of 

 deepening the faith in science of the practical man. Faith 

 in the results of pure science is more robust in Germany 

 and the United States than in this country ; here we 

 cultivate more exclusively things which ripen quicklv and 

 yield an immediate return upon the capital invested, and 

 are inclined to turn aside from projects which, though 

 more profitable in the long run, will, so to speak, take a 

 long time before they corne into bearing. 



ZOOLOGY IN THE INDIAN EMPIRE. 



''PO the September number of Spolia Zeylaniea Prof. 

 Punnett contributes an imjX)rtant paper, illustrated 

 by two double coloured plates, on mimicry in Ceylon 

 butterflies, with a suggestion as to the nature of poly- 

 morphism. After, giving a list of the hitherto recorded 

 instances,- which are- relatively numerous in comparison 

 with the- extent of the fauna, the author points out that 

 this mimicry is far less striking among the living insects 

 than in. museum specimens.- Not only is this difference 

 apparent on the under surface of the wings when the 

 insects are at rest, but it is still more noticeable in the 

 mode of-flight, so that with very little experience the eye 

 learns to distinguish between the mimic and the mimicked. 

 In the well-known case of Papilio polyotes, with its three 

 phases of females, one of which closely resembles the 

 male of the same species, while the second mimics the 

 male of P. aristolochiae, and the third that of P. hector — 

 both the two latter being inedible, while the first is edible 



NO. 2143, VOL. 85] 



— the author observes " that though model and mimic may 

 be readily distinguished at rest, whether with wings ex- 

 panded or closed, yet the resemblance between them may 

 be sufficient to deceive such enemies as attack them when 

 flying. Such, however, is certainly not the case. The 

 mode of flight of P. polyotes is similar for all three forms, 

 and is totally distinct from that of P. hector and P. 

 aristolochiae. 



After referring to the distribution of the three species 

 and the relative numbers of the males and females of the 

 different forms in various localities, the author states that 

 the facts " are far from lending support to the view thai 

 the polymorphic females of P. polyotes have owed their 

 origin to natural selection in the way that the upholders 

 of the theory of mimicry would have us believe." 



For Prof. Punnett 's suggestion as to the origin of poly- 

 morphic females our readers may be referred to thf 

 original paper, as it is too long to quote, but it may be 

 m.entioned that Mendelism plays a part in the explanation. 

 Mimicry in other species, together with the natural 

 enemies of butterflies in Ceylon, is likewise discussed. 



In the same issue Mr. George Duncker, after mention- 

 ing that although the group is common in the fresh waters 

 of India and East Africa, none has been hitherto recorded 

 from those of Ceylon, states that during the summer of 

 1909 he succeeded in obtaining examples of four species — 

 one of which is new — of pipe-fishes of the famih 

 Syngnathid.-E from the rivers of that island. 



With the exception of one devoted to a South African 

 frog allied to Rana corrugata of Ceylon, the articles in 

 part iii. of the fifth volume of the Records of the Indian 

 Museum deal with invertebrates of various groups. Among 

 these papers is one by Dr. Annandale on a new genus of 

 psychodid Diptera from the Himalaya and Travancore. 

 based on a minute species from Darjiling, described 

 earlier in the present year by Dr. Annandale as Diplonema 

 superstes ; this now becomes Brunettia superstes, while 

 the new Travancore species is to be known as R. travan- 

 corica. In a second paper the same writer discusses the 

 Indian scalpelloid barnacles of the subgenus Smilium, 

 while in a third Mr. S. Kemp describes three new Indian 

 species of the marine decapod ff»nus Gennadas. Most 

 interesting of all is an article by Mr. C. A. Pavia on the 

 larvae of a common Calcutta mosquito, known as Toxo- 

 rhynchites immisericors. It was suspected that these larva- 

 feed on the larvae of another mosquito, Stegorjiyia fasciata. 

 frequently found in water contained in earthen vessels, and 

 experiment has proved the surmise to be true. The larva- 

 of T. immisericors feed, in fact, greedily on those of 

 Stegomyia, " and as S. fasciata, the yellow-fever mosquito, 

 is very common in earthern pots round Calcutta, one i> 

 iustified in assuming that T. immisericors plays an 

 important part in its destruction, in a manner which 

 would be of great moment in the event of yellow fever 

 being introduced into the country." R. L. 



THE ARRIVAL OF MAN IN BRITAIN.^ 



THE address dealt with the antiquity of man as revealed 

 in the geological record, and with the^ conditions 

 under which Palaeolithic man arrived in Britain. In the 

 Tertiary period the higher (Eutherian) Mammalia appear, 

 en pleine evolution, and afford the means of classifying 

 it into the following well-marked divisions : — (i) Thi- 

 Eocene, in which living families and orders appear and 

 there are no living genera. (2) The Miocene, in which 

 there are living genera and no living species. (3) Th. 

 Pliocene, in which the extinct species are preponderam 

 and living species appear. (4) The Pleistocene, in which 

 the living species are preponderant, and the extinct are 

 few in number ; Palaeolithic man appears. (5) The Pre- 

 historic, in which there are no extinct species of land 

 Mammalia, and man is in the stages of culture marked 

 by the use of Neolithic, bronze, and prehistoric iron imple- 

 ments. (6) The Historic period, in which the events are 

 recorded in history. 



In this classification the evolution of the Tertiary 

 Mammalia takes the shape of a genealogical tree with 



1 Abstract of the Huxley Memorial Lecture ''elivrreH before the Koval 

 Anthropological Inslitute on November 22 by Prof. W. Eoyd Dawkins, 

 F.R.S. 



