254 



KNOWLEDGE. 



[November 1, 1898. 



occulting body, at minimum, has still a portion projected 

 outside the central globe. I stated, however, that I was 

 only dealing with central eclipses. Without going into 

 calculations, which are somewhat operose, and for which I 

 have not just now the time, it can be seen that we can get 

 any variety of curve, from an almost straight line with 

 slight depression in centre to a deeply hollow curve. The 

 first results when only a very small portion of the bright 

 central globe is cut off or obscured, and the last when the 

 occulting body is nearly the same size as the primary, and 

 when, at minimum, a small portion only (as seen from the 

 earth) lies outside the bright globe. To get the exact 

 shape at minimum one would require to calculate the 

 change in light for several positions of the occulting body 

 very close together ; in fact, for more frequent intervals. 

 E. E. Makkwick, Col. 



LIGHT CUEYES OF OCCULTING BODIES. 

 To the Editors of Knowledge. 

 SiES, — On page 183 of the August number of Kno^nxedge 

 is the suggestion of worliing out the curves for bodies 

 which occult each other, as shown in variable stars. In 

 the case of ^ Lyr.p, this has been done by Prof. G. W. 

 Myers, Urbana, Illinois (University of Illinois), who pre- 

 sented his results at the " Conference," held at the Yerkes 

 Observatory, in 1897, October. The agreement between 

 the Argelander light curve and the Myers theoretical curve 

 was very remarkable. Chas. H. Rock\\'ell. 



The Observatory, Tarrytown, New York, 

 9th August, 1898. 



WEASEL AND YOUNG. 

 To the Editors of Knowledge. 



Sirs, — About Midsummer I was talking with a friend in 

 the country, when something crossed the road quite near 

 us. On being followed it resolved itself into an old weasel 

 and a young one ; the parent, having seized the latter 

 behind the ear, was leading or dragging her charge at a 

 gallop. The animals disappeared under some loose pieces 

 of wood, and by moving one of these gently I was enabled 

 to secure the young weasel in my handkerchief. This 

 wrapper was afterwards very attractive to the parent, who 

 could detect the odour left by the other, and she came 

 qivite boldly all around it, posing in the most interesting 

 attitudes, and with a prettily-earnest expression of face. 



On the next day I saw her lead another young one for 

 quite twenty yards along the road. A farmer friend tells 

 me that the old weasels (and foxes also) always lead their 

 young in this particular manner. 



It would be interesting to learn whether this habit pre- 

 vails in the carnivora generally ; it does not appear to 

 occur in the vegetable eaters. Chaeles A. Witchell. 



Acetylene gas was, during last month, put through a 

 somewhat severe ordeal at the Botanical Gardens, Edgbas- 

 ton, where a garden party assembled to witness a demon- 

 stration of the new illuminant there introduced into the 

 houses. Prof. Hillhouse has studied the light from two 

 points of view — injury to plants from evolved gases, and 

 relations with colour. He had failed to see the smallest 

 sign of any of those injurious effects which the combustion 

 of coal-gas had upon plants, while the most critical colours, 

 so far as artificial illuminants were concerned, came out of 

 the ordeal with success — the mixed shades of mauve and 

 magenta being as perfectly displayed as with the arc light, 

 and the various shades of yellow could hardly be more 

 distinguished in ordinary sunlight. 



Appalling possibilities for crime were suggested by Sir J. 

 Crichton Browne in his inaugural address to the Pharma- 

 ceutical Society this session. A connoisseur of poisons 

 could, by keeping his own microbes, slaughter hundreds of 

 innocent people without the slightest fear of his crime 

 coming to light. Even in a most minute post-mortem 

 examination, many of the comparatively new organic 

 poisons defy detection. 



The annual exhibition of the Royal Photographic Society 

 of 1898 does not, we think, mark any decided advance in 

 true photography. There is much in the exhibition that 

 is beautiful, and many of the studies display admirable 

 and clever work, but notwithstanding the general excellence 

 of the exhibits there is not one photograph which can be 

 singled out and branded as a masterpiece. If this forty- 

 third exhibition of the Royal Photographic Society is to 

 be of peculiar benefit to photographers, the benefit should 

 lie in clearing up the vexed question as to whether the 

 unworked photograph is to rank side by side with the 

 " faked " photograph. In this exhibition prominent posi- 

 tions have been given to studies so " worked up " that the 

 veriest tyro can see that shadows, high-lights, and much 

 detaU are the result of paint and pencil. The influence of 

 this upon the average photographer, whether he sends in 

 an exhibit, or whether he merely attends the exhibition to 

 learn, must be deleterious. 



We learn from a report recently issued by the Board oi 

 Agriculture, that the total amount distributed during the 

 financial year, 1897-8, to institutions in this country for 

 agricultural education and research was seven thousand 

 two hundred pounds, as compared with seven thousand in 

 the prenous year. Four colleges — namely, University 

 College of North Wales, Bangor ; Durham College of 

 Science ; University College of Wales, Aberystwyth ; and 

 Reading College — each received eight hundred pounds, and 

 the remainder was distributed in varying amounts down 

 to a minimum of fifty pounds. Considering that thirty- 

 two separate counties share in this grant, it will be 

 apparent that experimental work in cultivating the soil in 

 this country is economically performed as far as the 

 Government is concerned. 



Some very interesting ornithological news has lately 

 been received from New Zealand. A fourth specimen of 

 Xotoniis Mantdli, a large flightless rail, has been captured. 

 The last specimen of Notornis was captured some twenty 

 years ago, and it has long been considered extinct by most 

 people, although a few have clung to the idea that the 

 species yet lived hidden in some of the great marshes of 

 New Zealand. The name Xotoniis was originally given 

 by Owen to some fossil bones discovered in the North 

 Island, New Zealand. In 1849, a few years later, Mr. W. 

 Mantell obtained in the Middle Island a freshly-killed 

 Specimen of a flightless rail which was declared to be 

 of the same species as Owen's Xotoniis. A second speci- 

 men was obtamed in 1851, and a third in 1879. The 

 present specimen was killed by a dog in the bush ad- 

 joining Lake Te Anau. The skin and all parts of the 

 bird have been carefuUy preserved, so that we may look 

 forward to having some exceedingly valuable details con- 

 cerning this interesting bird. The fact that this fourth 

 specimen was a young female proves that the bird is by no 

 means extinct, and also that it is not easy to find. 



Electric traction is likely in the near future to become 

 a new power in the transmission of the " mail." Such an 

 electro-postal line as has been recently proposed would be 



