January 4, 1900] 



NATURE 



235 



Dr. Robert Wallace has republished as a separate leaflet 

 his letter to the Times of November 29, on the African horse- 

 sickness. The disease is a malarial fever produced by a minute 

 fungus which grows during the summer on the veldt, but whether 

 in water, on the soil, or as a parasite, is not yet ascertained. 

 Although not contagious, it is contracted by animals e.\posed to 

 the night air, especially in damp situations. The disease ap- 

 (lears annually, but only in certain seasons attains alarming pro- 

 portions. Its serious character may be gleaned from the state- 

 ment that some 95 per cent, of the animals afflicted succumb. 

 And unfortunately no effectual system of inoculation has yet 

 iieen discovered to check its ravages. Certain precautions are, 

 (lowever, mentioned, which render horses less likely to be at- 

 icked ; and we believe that horses fed on dry fodder, like those 

 1 the British cavalry, stand a better chance of escape than 

 :_;rass-fed animals. 



At a recent meeting of the Society of Arts, Mr. F. G. Aflalo 

 read a paper on the necessity for legislative regulation of sea- 

 angling. It was urged that angling from piers on the British 

 coast resulted in a very appreciable diminution of the numbers of 

 certain species of fishes, such spots being favourite feeding- 

 .yrounds for fish of several descriptions. It was not that each 

 boy that fished did much harm by himself, but the total catch 

 by the entire army of boy-fishers must be very large indeed. 

 And there is one very strong reason why legislation in regard to 

 restoring under-sized fish to the sea should be enforced 

 ■gainst the angler rather than against the steam-trawler. This 



that while most of such fish are irretrievably injured by the 

 lawler, the majority of those captured by the hook, if carefully 

 temoved, are little or none the worse for their temporary 

 sojourn in the air. It is admitted that a large destruction of 

 -mall fish takes place through trawling ; but the only remedy 

 for this would be to stop the industry altogether. On the other 

 hand, the return of small fish captured by the hook to the 



Iter is a comparatively easy matter to enforce. The general 



nse of the meeting supported the author's views. 



The greater portion of the December issue of the Zoologist 

 - taken up by the continuation of Mr. Distant's paper on 

 mimicry; the illustration of "active mimicry" forming the 

 subject of this section. Among many instructive examples, we 

 may call attention to one very curious case. During the last 

 decade gardens in Hamburg have been extensively planted with 

 the white-leaved variety of the maple, and the common white 

 butterfly has now accustomed itself to select that shrub on which 

 to settle. Had Hamburg been a terra incognita, observes the 

 author, there is little doubt that this practice would have been 

 recorded as a striking instance of passive mimicry. Although 

 not coming under the head of mimicry, we may mention that 

 an analogous change of habit is taking place among many 

 of the Argentine birds, which formerly built on the ground, j 

 lut, as planting increases, are beginning to nest in trees. | 



We learn from the U.S. Monthly Weather Review for j 

 ptember last, that the important international cloud work I 

 the Weather Bureau, on which Prof. F. H. Bigelow has 

 .Len"*engaged for several years, is now completed, and will 

 l)e published in the annual report of that department for j 

 ,' S9S-99. It will be remembered that about the middle of j 

 <* year 1896 several meteorological services co-operated in 

 living a series of simultaneous observations on the height and 

 motion of the ten standard types of clouds which have been 

 defined by the International Cloud Committee, and that the 

 observations were continued for at least a year. Those 

 undertaken by the Weather Bureau were divided into two 

 classes : { I ) Those made by means of two theodolites placed 

 at the end of a long base-line. These give the absolute height, 

 velocity, and direction of motion of individual clouds at Wash- 

 NO. 1575, VOL. 61] 



I ington. (2) Those made with nephoscopes at fourteen stations 

 I over the districts east of the Rocky Mountains, giving the rela- 

 tive velocity and direction of motion. The discussion of the 

 j data will show the distribution and average height of each type 

 i of cloud for every month, and the depth of the zone or hori- 

 j zontal belt in which each type may occur. A very important 

 I subject of investigation has been the determination of the direc- 

 i tion and velocities of the horizontal motions of the air in each of 

 the eight principal levels, on all sides of the areas of high and 

 j low barometric pressures as they move over the United States. 

 i This gives definite information regarding storm components, and 

 1 will enable us to look more closely into the various theories of 

 i cyclones and anti-cyclones ; it is stated that an attempt to in- 

 terpret the analytical equations of motion has led to a different 

 idea of the circulation in storms from that commonly taught by 

 meteorologists. 



Several drawings and reproductions of photographs of 

 I " the old moon in the young one's arms " are given in the 

 I Bulletin of the French Astronomical Society for December, 

 I 1899, with an article upon the subject of earth-shine, or 

 i la lumiere cendrie as it is termed in France. Curious views 

 have been held as to the reason why the whole dusky ball of 



our satellite can be seen near the time of new moon. Posidonius 

 thought that the moon was a diaphanous body, and that the 

 rays of the sun passing through it caused the dull appearance 

 observed. Tycho Brahe suggested that the appearance was 

 produced by the illumination of the moon by Venus, and it was 

 left to Leonard de Vinci to discover the real cause, namely, the 

 reflection by the moon of sunlight reflected from the earth. The 

 accompanying illustration of the phenomenon is from a photo- 

 graph obtained by M. F. (^uenisset. 



Appendix III. to the Ke^N Bulletin oj Useful Information 

 for 1899 consists of a directory of the staffs of the Botanical 

 Departments in these islands, in the colonies, and in India. 



The discovery of several lines in the infra-red spectrum of 

 argon or of some associated gas is announced by Messrs. R. . 

 Nasini, F. Anderlini, and R. Salvadori in the Atli dei Lincei^ 

 viii. (2) 10. The spectrum, of which a photograph is given, 

 was obtained from the residual gas of one of the fumaroli of 



