Jtme 28, 1877] 



NATURE 



169 



Iowa Weather Report. — We observe from a circular 

 issued by Prof. Gustavus Henrichs to the volunteer ob- 

 servers of Iowa (U.S.), that his report of the observa- 

 tions made at the meteorological stations of that State 

 during 1876 is to be published as an Appendix to the 

 Report of tl:e foa'a S/u/r Ai^ricHltiira! Society, and that 

 as the monthly reports are published in fuUy twenty of 

 the newspapers, the Wcatlicr Rcvieiv will be discontinued. 

 The ffVi^/Z/tv /;'(■/(>;■/ about to be published will embrace 

 an account of the meteorological system now in full opera- 

 tion over the State, and discussions of the rainfall, storms, 

 and other phenomena, the normals which have been 

 ascertained for different localities, and the detailed obser- 

 vations made at the Central Weather Station. 



OUR ASTRONOMICAL COLUMN 



The Saturnian Satellite, Hyperion. — Prof. 

 Asaph Hall, in Astron. Nack., No. 2,137, publishes an 

 ephemeris of this faint object about the approaching op- 

 position of Saturn, with the view to facilitate observations, 

 especially near the conjunctions. He remarks that 

 although the satellite was discovered (by Bond and 

 Lassell) nearly thirty years since, the difficulty of observ- 

 ing it has been so great that no satisfactory determination 

 of its orbit has been practicable ; most of the observations 

 being made near the elongations, the position of the plane 

 of the orbit is not accurately deducible therefrom, though 

 it probably does not coincide with the plane of the ring, 

 but appears to lie between those of Titan and Japetus. 

 With the view to assist observation in the present year 

 Prof A. Hall has calculated elements from his observa- 

 tions in 1S75, which may be stated as follows : — Peri- 

 saturnium passage, 1S75, August 24'oo36 mean time at 

 Washington ; distance of perisaturnium from the node 

 40° o', eccentricity o'i2 5, semi-axis major 2I4"'22, period 

 of revolution 2r3il3 mean solar days. For the reason 

 stated above it is supposed for this approximate orbit that 

 its plane coincides with that of the ring, the node of which 

 on the earth's equator is assumed to be in 126^ 9''!, and 

 its inclination thereto 7' 3''8. From these data auxiliary 

 quantities and an ephemeris for Washington midnight, 

 August l-September 15, are added, and it is suggested 

 that with the aid of the former comprising the interval 

 June I -December 28 a more accurate calculation may be 

 made by Mr. Marth's formulae. 



Taking the solar parallax at 8"-86 Prof. A. Hall's 

 elements would give for the mean distance of Hyperion 

 from the centre of Saturn 914,000 miles, distance in peri- 

 saturnium 800,000, in aposaturnium 1,028,000 miles. 



The first computation of the orbit of this satellite was 

 by the late Prof G. P. Bond, of Cambridge, U.S., from 

 his distances observed between 184S, September 19, and 

 January 12 following; his period of revolution is 2i"i8 

 days, mean distance 214", eccentricity o'l 15 ; the elements 

 will be found in \h^ Proceedings o{\\\^ American Academy 

 of Arts and Sciences. 



The Triple-Star 7 Camelopardi. — The third com- 

 ponent of this triple star was detected by Baron Dem- 

 bowski on .September 28, 1864, having been overlooked by 

 Struve at Dorpat, who measured A and B in 1831, his 

 mean result being i83i'57, pos. 238'32", dist. 25647" 

 The Galarate epoch for the new companion is (A C) 

 i865"33 pos. 308^83, dist. i"'245. Baron Dembowski 

 says the object was one of great difficulty for his refrac- 

 tor principally on account of the sombre hue of the star 

 C, which did not appear always of the same intensity ; 

 referring to his observations at the epoch i865'25, 

 he remarks, " EUe avail alors ui.e couleur de cendre 

 mouillde ; je n'ai jamais vue d'(?toile aussi sombre.' His 

 magnitudes of C in 1864-5 vary from 7'o to 9'o, while in 

 the middle of November, 1865, he could not perceive the 

 least trace of the star. Mr. Crossley measured A B at the 

 end of December, 1873, but has no reference to the third 



star. The object will be worth watching on the score of 

 variability and the unusual duskiness noted by the 

 Galarate observer. 



The Cape Astronomical Results for 1874.— -Mr. 

 Stone has just circulated his volume of observations made 

 at the Royal Observatory, Cape of Good Hope, in 1874, 

 being the thirteenth separate publication which has ema- 

 nated from this important and active astronomical estab- 

 lishment since the year 1871, when Mr. Stone undertook 

 its direction. We believe there is not a refinement in 

 observing or computing which is not introduced into the 

 Cape work, and the results have consequently a very high 

 value, comparable with the best work of the kind pub- 

 lished by the great European and American observatories, 

 where attention is given to stellar astronomy. The volume 

 for 1874 contains the mean positions of 1,246 stars, in- 

 cluding all Lacaille's stars of the Ca'luin Australe Stelli- 

 fertiin, which now fall between 155^ and 165° of north 

 polar distance, and some additional ones in the same 

 zone. Lacaille's stars between N.P.D. 145- and 155° were 

 similarly observed in the course of the year 1875, ^nd 

 those between N.P.D. 135° and 145° in 1876, the reduc- 

 tions to mean places for the former zone having been 

 completed at the beginning of the present year. A com- 

 plete determination of the accurate places of all Lacaille's 

 stars, founded on the Cape observations, is therefore in a 

 very forward state. 



As an appendix to this volume of Cape Observations, 

 Mr. Stone presents tables intended to facilitate the com- 

 putation of star-constants, which appear likely to prove 

 of very great service to the practical astronomer. By a 

 slight modification of Bessel's form for star-corrections he 

 has been able to tabulate the quantities in a very con- 

 venient and compendious manner, so that the whole com- 

 putation occupies but a short time. Mr. Stone hopes that 

 the use of these tables may render it unnecessary to give 

 star-constants for every star contained in future cata- 

 logues, the labour of forming which, and of insuring their 

 accuracy is very great. It is probable, as he observes, 

 that the use of star-constants in various catalogues has 

 been in many cases extended beyond the time when they 

 could be introduced with a due regard to the precision 

 required in modern stellar astronomy, which will be 

 obviated by the use of the tables in question. It is under- 

 stood tiiat Mr. Stone liberally ofters to supply a copy of 

 these tables to anyone who would find them of real service, 

 and who will make application for them. A few remarks 

 on the modus operandi with the tables are reserved for a 

 future column. 



THE BRITISH ASSOCIA TION AT PL YMOUTH 



FEW towns in the United Kingdom have so much to 

 interest alike the scientific and the general visitor 

 as Plymouth ; and the meeting there of the members 

 of the British Association in August next should prove 

 alike pleasant and profitable. For the general visitor it 

 will perhaps be enough that the Plymouth Hoe is one 

 of the finest promenades in England, and that the land- 

 scapes of the neighbourhood are at once most varied and 

 most attractive. The man of science will be able to enjoy 

 all this and a good deal more. The zoologist may if he 

 pleases revel in dredging expeditions in and off the Sound, 

 which are sure to yield an ample reward. For the 

 mechanician there are three of the most no able works of 

 modern engineering skill to inspect — the Edoystone Light- 

 house, the Plymouth Breakwater, and the Royal Albert 

 Bridge, while the Government dockyards and factories at 

 Devonport and Keyham, and the war vessels which stud 

 the Hamoaze, will have a general as well as a special 

 interest. One of the most enjoyable excursions of the 

 Exeter meeting was that to the Three Towns, on which 

 occasion the Government establishments were visited and 

 gunnery and torpedo practice, with all the latest electrical 



