Jaxuaky 1, 1897.] 



KNOWLEDGE 



13 



substances opaque to light ; and I think I am also right in 

 stating that it has been demonstrated that it is not carried 

 by particulate matter, and therefore not akin to our sense 

 of smell. The explanation which seems to me to have 

 some degree of probability is, that the female moth is 

 capable of emanating rays of the same nature as the 

 X rays in the luminiferous ether, and that the male moth 

 has an organ of sensation (probably situated in the 

 antenna^) capable of receiving these rays. 



If such is the case it is easy to put the matter to the 

 test, for if the female wingless moth called "vapourer 

 moth" emanates these rays, then it would be possible to 

 take a photograph with such a moth as the source of our 

 X rays. 



Time and material have been wanting, or I should long 

 ago have made the experiment. 



If some of your readers could put the matter to the test 

 by making this experiment, I should be glad to know 

 whether a negative or positive result is obtained. 



I should also be glad to know whether it has ever been 

 observed that moths are attracted by a working Crookes 

 tube. W. F. Lloyd. 



The Eoyal Infirmary, Windsor. 



« : 



THE LEAF-CUTTER BEE. 

 To the Editors of Knowledge. 

 Sirs, — I noticed in the November Number of Kxo^xedge 

 a short account of that most intelhgent insect, the leaf- 

 cutter bee. Mr. Duncan does not give due credit to this 

 little architect when he writes: "This manoeuvre is 

 repeated several times until ten or twelve pieces have been 

 cut. The bee then enters the tunnel and begins to twist 

 and fold the leaves, making them fit together into a sort 

 of funnel-shaped cone, something like a thimble." As 

 soon as the leaf-cutter bee has made her burrow she 

 flies off and selects a rose-bush of the " tea " type, from a 

 leaf of which she first cuts a circular piece somewhat 

 larger than the diameter of the bm-row, into which she fits 

 it at the bottom. She then returns to the same leaf and 

 cuts an oblong, wedge-shaped piece, flies with it fixed 

 between her jaws and third pan- of legs to the burrow, 

 down which she takes it thin edge first, and, without any 

 delay, fits it into the concave bottom-piece. Again she 

 returns to the bush to cut another oblong piece of exactly 

 the same size, returning to the burrow in exactly the same 

 way, placing this second oblong piece with the edges over- 

 lapping the first ; and so on, backwards and forwards to the 

 bush and burrow, each piece being laid in its place, until 

 the sides often consist of a dozen or more oblong, wedge- 

 shaped pieces. Then the bee makes repeated journeys to 

 the flowers, collecting poUen and nectar with which to 

 make the dehcious " pudding " for her future progeny- 

 one pudding and one egg ; then as many as a dozen 

 circular pieces, cut one by one and placed in exact position, 

 so that they form the cover of the first cell and foundation 

 of the second. " Order was Heaven's first law," which 



law insects obey. Fred. Enock. 



» 



Rr^ES AXD OaHAMS. 

 To the Editors of Knowledge. 

 Sirs, — Your correspondent, Mr. Charles A. Schott, calls 

 into question the statement in my paper that rimes have 

 been found on the banks of the Potomac. 



My authority is M. Napoleon Ney, president of the 

 Societe de Gi'ographie Commerciale (Paris). 



As it is perfectly well known that Scandinavians visited 

 the coasts of North America, surely it is not " palpably 

 absurd" that they should be credited with setting up an 

 inscription there as elsewhere. 



Gerteude Buefobd Rawlings. 



Scitnw Notts. 



The aim of civilization should be to harmonize all the 

 powers of mind in the community as well as in the indivi- 

 dual. There should be close bonds of sympathy between 

 men of science, art, and literature, so that the best thoughts 

 and the best work in each shall meet with equal recogni- 

 tion. This spirit of broadmindedness is nurtured by the 

 Royal Societies Club, where, a few days ago, Sir Edward 

 •J. Poynter, President of the Eoyal Academy, was enter- 

 tained at dinner. On that occasion Fellows of the Royal and 

 other scientific societies, members of the Eoyal Academy, 

 and distinguished men of letters gathered together at the 

 same board, and the ties between them were strengthened 

 and more closely drawn by the meeting. " Literature, 

 Science, and Art " were combined in one toast, which was 

 responded to by three representative men, Dr. Conan 

 Doyle, Prof. Eay Lankester, and Mr. Wyke BayUss. In 

 replying for science. Prof. Lankester remarked that some- 

 times there appeared to be antagonism between it and art, 

 but really there was none. Art depicts lovely things, 

 while the duty of science is to explain rather than create ; 

 yet both act together in revealing the harmony and beauty 

 of the works of natm-e. 



The Davy Medal (of the Eoyal Society) has been 

 presented to Prof. Henri Moissan for the isolation of 

 fluorine and the use of the electric furnace Ln the prepara- 

 tion of refractory substances ; the Copley Medal to Prof. 

 Carl Gegenbaur for his researches in comparative anatomy, 

 and especially in the history of the vertebrate skeleton ; 

 the Eumford Medal to Profs. Lenard and Eontgen for their 

 investigation of the phenomena produced outside a highly- 

 exhausted vacuum tube through which electrical discharge 

 is taking place ; the Darwin iledal to Prof. Giovanni 

 Battista Grassi for his important discoveries, especially on 

 matters directly related to Darwin's speculations. A 

 Eoyal Medal has been given to Sir Archibald Geikie for 

 his original contributions to geology, and to Prof. Charles 

 Vernon Boys for his invention of quartz fibres, improve- 

 ment of the radio-micrometer, development in the art of 

 instantaneous photography, and for his determination of 

 the value of the constant of attraction. 



Dr. Ludwig Mond, F.E.S., wiU always be gratefully 

 remembered by those who desire an opportunity for origi- 

 nal work in pure chemistry or physical chemistry, and 

 also by the public at large for the munificent gift of a new 

 research laboratory (to be called the Davy-Faraday Ee- 

 search Laboratory), which adjoins the Eoyal Institution. 

 In addition to purchasing the freehold and fitting up the 

 building. Dr. Mond has also provided an endowment for its 

 maintenance, at a total cost of about one hundred thousand 

 pounds. The laboratory, opened by the Prince of Wales 

 on •22nd December, is fitted throughout with the newest 

 and most improved apparatus. In the basement there 

 are an electrical room, with a battery of twenty-six accu- 

 mulators, a constant temperature room, a room for thermo- 

 chemistry, another for pyro-chemical research, and an 

 electric furnace for smelting. The higher floors are de- 

 voted to working laboratories, including an optical room, 

 a photographic room, and a room for the preparation of 

 chemicals. There is also a large Ubrary, and every other 

 provision for smoothing the rough paths of original re- 

 search work, - — >-•-. — 



The process of vulcanizing india-rubber by means of 

 bisulphide of carbon, and the operations incidental thereto, 

 have been condemned by the Home Secretary as dangerous 

 or injurious to health. 



