446 



NATURE 



[Aprils, 1875 



method for some years previously, and had communicated it to 

 several mathematicians, but omitted it frem my elementary 

 "Geometry of Conies" {1872), hoping that I might soon have 

 leisure to develop it more fully in a larger work. Shortly before 

 the publication of my article in the Alessnigcr, Mr. R. W. 

 Genese rediscovered the circle and its properties. Mr. Day uses 

 this circle in his work on the Ellipse (1868), but has overlooked 

 one of its characteristic properties. C'. Taylor 



St. John's College, Cambridge 



Destruction of Flowers by Birds 

 "P. B. M.," in Nature for April i, refers to the destruction 

 of the crocuses in a garden at Burton on-Trent, by birds. This 

 may also be observed in the flower-beds in Hyde Park, near 

 Park Lane. It is remarkable, however, that while the yellow 

 flowers are very extensively destroyed, the white ones remain 

 uninjured. The reason for this is not very evident, and I should 

 be glad to see it explained. C. Roherts 



Bolton Row, April 6 



OUR ASTRONOMICAL COLUMN 

 Red Stars, &C.— We lately referred to the incom- 

 pleteness of the first catalogue of isolated red stars formed 

 in 1866 by Prof. Schjellerup of Copenhagen. In the last 

 part for 1874 of the \ icrtcljahrssclirift dcr Asirouomischeii 

 Gesellschafi is a second and much extended catalogue by 

 the same "astronomer. The first list, which was published 

 in Astron. Nach., No. 1,591, vi'ith additions in No. 1,613, 

 contained 293 stars ; in the new catalogue the number is 

 upwards of 400. The notes attached have also been con- 

 siderably extended. The author remarks that his first list 

 was instrumental in the discovery of a number of variable 

 stars, and that Secchi found in it many stais of his 

 Type III. and the whole of Type IV. Those who are 

 interested in the discovery and observation of variable 

 stars will do well to provide themselves with Schjellerup's 

 new catalogue. The same part of the \ icrtcljalirsschrift 

 (which accidental circumstances have delayed in publica- 

 tion) contains an ephemeris of most of the variable stars 

 for the year 1S75 ; also a notice of Prof. Schcinfeld's 

 researches on S Cancri from observations to April 1872 ; 

 the period is found to be gd. i ih. 37m. 45s., and the epoch 

 of minimum is fi.xed to 1867, August 31, at i4h. 12m. 15s. 

 Paris mean time. This star has long been known to 

 resemble Algol in its law of variation ; the diminution of 

 light commences somewhat suddenly, 8i hours before 

 minimum, and about 13 hours after minimum the star 

 recovers the brightness at which it continues to shine for 

 the greater part of its period. 



The Comet of 1S12. — Of those comets discovered 

 during the present century which appear to have periods 

 of revolution approximating to that of H alley's Comet, 

 it is probable that the one detected by Pons at Marseilles 

 on the 20th of July, 181 2, will be the first to revisit these 

 parts of space, and this visit may be looked for within a 

 tew years' time. We are indebted for our knowledge of 

 the elliptical form of this comet's orbit to Encke, who, 

 working when assistant at the Observatory of Seeberg 

 under the guidance of his "great tutor Gauss," discovered 

 early in the year 181 3 that no parabola would represent 

 the observations, and that an ellipse with a period of 

 revolution rather exceeding seventy years was very far 

 preferable. His further and definitive investigation of the 

 elements is found in Zcitschiift fiir Aslionoinic, il. p. 

 377. He made use of observations between July 23 and 

 iSept. 27, taken at Paris, Marseilles, Vienna, Milan, See- 

 berg, Bremen, Berlin, and Prague, no in number, and 

 finally arrived at an elliptical orbit, with a period of 

 70-69 years, the probable uncertainty of this result allow- 

 ing of it bein:4 as short as 66'54 years, or as long as 75'27 

 years. Encke does not appear to have had the advantage 

 of the original observations taken at Paris, which appear 

 in the folio volume of observations 1810-20, nor yet of the 

 original obseivations by Flaugergues at Viviers, which 



were not printed until the end of the year 1820, when they 

 found their way into Zach's Correspondance Astionomique, 

 Mr. W. E. Plummer,of the University Observatory, Oxford, 

 has reduced the Paris and Viviers oljservations with every 

 care, and, making use of Leverrier's Solar Tables, has 

 deduced an ellipse quite verifying Encke's computations ; 

 he has hopes of being able to assign limits to the period of 

 revolution. We are also informed that the return of this 

 comet is engagingattention at the Observatory of Strassburg, 

 and that under Prof. Winnecke's superintendence sweeping ■ 

 ephemerides will be prepared there to facilitate the redis- 

 covery of the comet. It approaches nearer to the orbit 

 of Venus than to that of any other body in the planetary 

 system, but there could have been no material perturba- 

 tion from this cause during the last appearance. The 

 comet was detected by Bouvard at Paris on August I, 

 1812, and it was also independently discovered on July 31 

 by Wisniewski (the last observer of the great comet of 1 8 1 1 ), 

 at Novo Tcherkask, as stated in a letter from Von Fuss to 

 Bode, though he is not credited with this discovery in 

 our comelary catalogues. The other comets which appear 

 to have periods of revolution of similar length are the 

 comet of 181 5, usually known as Olbers' Comet, which is 

 the subject of a masterly investigation by Bessel in the 

 Berlin Memoirs, 1812-15 ; the comet discovered by De 

 Vico at Rome, 1846, February 20, of which the best orbit 

 is by Van Ueinse, in his " Inaugural Dissertation," Ley- 

 den, 1849 ; and the comet detected by Brorsen at Altona, 

 1847, July 20, which has been calculated by D'Arrest and 

 Gopld, but may yet admit of further investigation. 



METEOROLOGY IN ENGLAND 



THE address of the President and Report of the 

 Council of the Meteorological Society of England 

 for the present year will be read with a lively interest, 

 awakened and strengthened by a gro'ving conviction that 

 the Society has reached a critical turning point in its his- 

 tory. Hitherto the Society has been regarded as little more 

 than an association of amateur meteorologists, — the 

 national work, falling properly within the province of 

 such a society, of collecting the data of observation for 

 the elucidation of the laws of the weather and climate of 

 England, having been independently carried out by their 

 late energetic, able, and popular secretary, Mr. Glaisher, 

 whose great and in many respects valuable labours in 

 this department are somehow passed over in the docu- 

 ments before us. 



The Society, however, has now resolved to undertake 

 the work of collecting meteorological statistics, and in 

 carrying out this resolution has already established ten 

 stations pretty well distributed over different districts of 

 England. It is fitting that on private observers should 

 fall the labour of investigating Climatic Meteorology, 

 leaving the Govemm.ent to look after the physical side of 

 the science. In making it imperative on all their observers 

 that verified instruments alone be used, consisting of at 

 least a barometer, dry and wet bulb thermometers, maxi- 

 mum and minimum thermometers, and a rain gauge ; 

 that the adoption of Stevenson's Thermometer Box be a 

 sine quA noii, and that it be not placed within ten feet of 

 any wall ; that the rain gauge has its rim placed one foot 

 above the ground ; and that the hours of observation be 

 9 A.M. and 9 P.M. — the Society deserves our hearty 

 commendation. 



We must, however, point to a serious om.ission in the 

 system of observation which has been adopted. No im- 

 perative condition is laid down, and no recommendation 

 made, so far as we can see, with reference to the vital 

 question of the height of the thermometers above 

 the ground. If this point be not definitely settled 

 and made an imperative condition of observation, the 

 Society will collect materials on which no scientific in- 

 quiry into the climate of England can be based, and on 

 which little, if any, scientific value can be placed. The 



