258 



KNOWLEDGE. 



[November 1, 1897. 



* 



A CONGRESS, having for its object the international pro- 

 tection of birds useful to European agriculture, is to be 

 held at Ais-en-Provence during the week commencing on 

 November 9th. All communications with regard to the 

 congress should be addressed to " Le Secretariat General, 

 Grand Hotel Sextius, Ais-en-Provence." 



Next year the British Association will meet at Bristol, 



and in 1899 at Dover. 



— *-*^ — 



A modest genius, James Bowman Lindsay, who lacked 

 the art of self-advertisement, first discovered wireless 

 telegraphy and fully appreciated the great possibihties of 

 the invention, but he was unable to secure sufficient public 

 attention to carry his idea into the domain of practical 

 utility. He conceived the idea in 1831, and in 1857 he 

 transmitted messages across the Earl Grey Dock without 

 the aid of wires ; while later on he made calculations tending 

 to show that by selecting two stations in Britain, one in 

 Scotland and one in Cornwall, and two corresponding 

 stations in America, it would be possible to send messages 

 across the ocean without the intervention of a cable. 



The British Consul at Amoy says, in a letter to the 

 Secretary of the Association of Chambers of Commerce : 

 "My long residence in the East has taught me that the 

 Chinese and Koreans are very superstitious; they will 

 often buy small articles like biscuits, sweets, cosmetics, 

 needles, thread, matches, soap, scent, medicines, etc., for 

 the sake of a lucky label ; and they will as often refrain 

 from buying an article because it has to them an unlucky 

 label. The colouring of a label is as important as its 

 design. Some colours and combinations of colours are, 

 to the Chinese and Korean mind, unlucky ; other colours, 

 though not unlucky, are considered as only appropriate to 

 certain commodities." 



SOME NEW VIEWS AS TO THE PLANET 



VENUS.-II. 



By Camille FLAiiJiARioN, F.R.A.S., 



Author of " Astronomie Populaire," " Les EtoiUs," " Les 



Terres du del," " La Planete Mars," etc. 



AMONGST the remaining observations of any im- 

 portance I can see only those of Maedler, made 

 in 1833 and 1836. The reports of these ob- 

 servations are also in my possession.* This 

 astronomer, who just then had achieved con- 

 siderable progress in the study of the plauet Mars, begins 

 by saying that he has " never noticed any spot properly 

 so described, save, perhaps, what he observed on the 7th 

 April, 1836," except the diminution in brilliancy from the 

 limb to the terminator, or especially the irregularities of 

 the variations at both horns of the crescent. 



" We should not wish," he writes, " like Sehroeter, who 

 made a series of observations similar to these, to deduce 

 from them an exact period of rotation, for we are satisfied 

 that this time of rotation cannot be ascertained from 

 observations made upon the shape of the horns of Venus, 

 especially when all other elements of rotation are wanting. 

 But the variations in the outline of the horns which we 

 bave noted, at times with a surprising rapidity, if they be 

 not altogether wanting in objective reality, clearly are 

 quite incompatible with the Bianchini period, or any other 



* Fragments sur les Corps Celestes du Systime Solaire, by Beer 

 and Maedler. (Paris, 1840.) 



period of like duration ; and, on the other hand, more 

 than one sign seems to be in favour of Cassini's period. 



" We willingly admit that there may occur optical 

 deceptions in such determinations of the shape of the 

 cusps and of the elliptic outline of the phase of Venus, 

 which may rest upon no other foundation than the 

 observer's personal opinions ; but we consider it impossible 

 to look upon a whole series of observations such as these 

 as mere errors without better reason for so doing. 

 Especially the remarkable variations of the southern cusp 

 cannot by any means have been caused solely by our 

 atmosphere, or by the telescope, for then it must have 

 been seen in the case of the northern hom ; however, 

 if they bear any relation to the rotation of Venus, such 

 rotation cannot possibly have a period of several weeks." 



It was important to quote these remarks here. And 

 we may add that since they appeared, astronomers no 

 longer consider the rotation of Venus as taking place from 

 south to north, or, as Maedler expresses it, "along the 

 limit of light," but "perpendicularly to that line." This is 

 a somewhat drastic change in the appreciation of the 

 planet's motion, and one, too, which is no more justified 

 by observation than the former. Gradually, however, the 

 southern cusp came to be considered as approximately 

 marking the situation of the south pole, and the northern 

 cusp as representing the north pole. 



(6.) In 1839, at the Observatory of the Roman College, 

 Father de Vico, and his colleague, Palomba, threw them- 

 selves with great ardour into the task of verifying Bian- 

 chini's observations, and believed that they could recognize 

 the circular spots marked on his map.* They made more 

 than ten thousand observations, and satisfied themselves 

 of the motion of those spots. Indeed, De Vico precisely 

 defined the period of rotation as 23h. 21m. 21-93453. 

 According to the observations of 1839, the angle of 

 inclination was eighty degrees, while according to those of 

 1810 it was between fifty and sixty degrees. The results of 

 these observations were discussed by M. Schiaparelli with the 

 care and authority which he brings into all his researches,! 

 and he demonstrated that the above value was not founded 

 upon a sufficient agreement between weU-established 

 markuigs on the planet. In fact, De Vice's result may be 

 said to have been derived from his simply begging the 

 question, since in order to account for the changes observed 

 he adopted Schroeter's period of 23h. 21m. 193. as a basis 

 of computation ; for, after all, even those changes are, by 

 the Roman astronomer's own showing, as doubtful as 

 anything can be. Indeed, he himself declares that those 

 spots are uncertain, undefined, smoky, and so like to each 

 other that one can hardly help confusing them. We feel 

 that here again it is a question of luminous effects, or 

 atmospheric appearances. Besides, after the masterly 

 manner in which Dr. Schiaparelli dissected the subject, 

 De Vico's period can no longer lay claim to any solid 

 foundation, and must disappear. 



(7.) Whilst thus overthrowing the idea of a brief period 

 of rotation as not founded upon sufficient observation, 

 M. Schiaparelli, m his turn, has proposed that the time of 

 rotation should be assumed to be identical with that of 

 the revolution of the planet, i.e., equal to 221d. 17h. 

 According to this hypothesis the planet would revolve 

 around the sun, constantly turning the same face towards 

 him, as the moon does towards the earth. On the side 

 facing the sun daylight and heat would then prevail 

 indefinitely, while the opposite side would remain per- 



* Memorie intorno a parecchie osservazioni faffe nella specola in 

 Collegia rotnano, 1839, 1840, e 1842. 

 ■f- Considerazioni std moto rotatoria delta pianefa Yenere, 1890. 



