206 



NATURE 



{June 28, 1888 



and Nebulae." It will be published shortly by Messrs. Roper 

 and Drowley. 



The Fifteenth Annual Report of the progress of the 

 Geological and Natural History Survey of Minnesota, by Mr. 

 N. H. Winchell, State Geologist, has been issued. This Report 

 relates chiefly to the geology of the iron-bearing rocks. It seems 

 that during the last two years great interest has been manifested 

 with regard to the iron industry in Northern Minnesota. 



We have received Part 3 of the twenty-first volume of the 

 Journal and Proceedings of the Royal Society of New South 

 Wales. Among the contents are papers on Port Jackson silt 

 beds, by F. B. Gipps ; some New South Wales tan-substances, 

 parts 3 and 4, by J. H. Maiden, Curator of the Technological 

 Museum, Sydney ; soils and subsoils of Sydney and suburbs, 

 by J. B. Henson ; quarantine and small-pox, by J. Ashburton 

 Thompson ; on the presence of fusel-oil in beer, by W. M. 

 Hamlet ; autographic instruments used in the development of 

 flying-machines, by Lawrence Hargrave. 



Part i of the seventh volume of the "Encyclopaedic 

 Dictionary" (Cassell and Co.) has just been issued. This care- 

 fully-compiled work, as we have repeatedly had occasion to note, 

 contains all the words in the English language, with a full 

 account of their origin, meaning, pronunciation, and use. 

 Great pains are taken to secure that scientific terms shall be 

 properly explained. 



Messrs. Oliver and Boyd are about to publish " India in 

 1887, as seen by Robert Wallace, Professor of Agriculture and 

 Rural Economy in the University of Edinburgh." The author 

 was four months in India and Ceylon, and made inquiry as to 

 the breeds of cattle and horses, and as to the condition of 

 native agriculture, soils, irrigation, &c. The work contains 

 290 illustrations. Prof. Wallace especially wished to " learn 

 in an unmistakable manner what fruits the Cirencester College 

 training had borne." 



We have received Parts 1 and 2 of "The Speaking 

 Parrots," by Dr. Karl Russ (Upcott Gill). Much useful 

 information is given as to the purchase and reception of parrots, 

 the cages in which they ought to be kept, their food, the best 

 way of taming and training them, the preservation of their 

 health, and as to their diseases. 



An Australian edition of Longmans' " School Geography," by 

 Mr. George G. Chisholm, has just been issued. For this 

 edition the sections on Australasia and the British Isles have 

 been entirely re-written, and modifications have been made in 

 other parts of the text with the view of calling attention to 

 matters of special interest in Australia and New Zealand. 



A new catalogue of mathematical works has been issued by 

 Messrs. Dulau and Co. 



The current number of the Technology Quarterly opens with 

 an interesting paper, by Mr. James P. Munroe, on the beginning 

 of the Massachusetts Institute of Technology. The Institute 

 was legally established on April 10, i86r, after more than two 

 years of almost constant effort in the face of opposition and 

 discouragement. 



It has been decided that the Miss Williams Scholarship for 

 Women, of the annual value of ^20, tenable for three years 

 shall be offered at the entrance scholarship examination at 

 University College, Cardiff, on September 18, and that it may 

 be held with a College exhibition. As it is specially intended 

 to encourage the higher education of women in Wales, preference 

 will be given to the children of Welsh parents. 



A collection of American pottery for the American National 

 Museum is about to be made by Dr. David T. Day of the United 

 States Geological Survey. Science says that the collection of 



Sevres pottery presented by the French Government is an ex- 

 ceedingly fine one, as is also that of Japanese ceramics ; and the 

 department of Indian pottery is not approached elsewhere in the 

 world. But the Museum possesses very little modern American 

 pottery. 



The additions to the Zoological Society's Gardens during 

 the past week include a Macaque Monkey {Macacus cynomolgtis). 

 from India, presented by Mr. A. B. Parker ; a Larger Hill- 

 Mynah (Gracula intermedia) from North India, presented by 

 Mrs. M. von Kornatzki ; two Naked-footed Owlets {Athene 

 nochia) from France, presented by Miss Pierce ; a Swainson's 

 Lorikeet ( Trichoglossus novce-hollandice) from Australia, presented 

 by Mr. H. A. Hankey ; two Loggerhead Ducks (Tachyeres 

 cinereus) from the Falkland Islands, presented by Mr. Archibald 

 McCall ; a Duyker-bok (Cephalophus mergens g) from South 

 Africa, a Red-legged Partridge (Caccabis rufa), a Barbary 



Partridge (Caccabis petrosa), five Pigeons (Columba ballii) 



from Teneriffe, deposited ; a Bennett's Wallaby (Halmotitrus 

 bennetti ? ), two Long-fronted Gerbilles (Gerbillus longifrons) 

 born in the Gardens ; a Yellow-legged Herring Gull (Larus 

 cachinnans), bred in the Gardens. 



OUR ASTRONOMICAL COLUMN. 



Rotation Period of the Sun from Facul^.— The fifth 

 part of vol. iv. of the Publications of the Astrophysical Observa- 

 tory at Potsdam has recently appeared, and contains a deter- 

 mination by Dr. J. Wilsing of the rotation period of the sun 

 from observations of faculae. The previous determinations of 

 the solar rotation have been based upon observations of the 

 spots, or upon the relative displacement of lines in the spectra 

 of the east and west limbs, for, as faculae can usually only be 

 seen well when near the limb, and therefore can seldom be 

 watched for more than three consecutive days, and as they 

 often undergo rapid changes, they did not seem well suited for 

 such a discussion. Their irregular and often straggling shapes, 

 too, render measures of their positions much less precise than 

 those of spots. Notwithstanding these difficulties Dr. Wilsing's 

 inquiry seems to have met with a measure of success. Of the 

 faculae shown on the solar photographs taken at Potsdam from 

 1884 March 14 to August 31, 144 groups were seen at three or 

 more different epochs, at intervals of one or more semi-rotations. 

 Arranging these according to their distribution in solar latitude, 

 in zones of 3 wide, Dr. Wilsing finds practically the same rota- 

 tion period for each zone from + 24" to - 33 , the difference 

 from the mean of the daily angular motion only exceeding 2' in 

 a single instance, and in many cases amounting only to 20" or 

 30". As these differences are so small and follow no law, it would 

 appear that, whilst, as Carrington and Spoerer have shown, the 

 different spot zones have different rates of rotation, the layer of 

 the faculae rotates as a whole. Since the faculae are certainly at 

 a higher level than the spots, this conclusion is one which will 

 fail to be accepted until we have much further and more con- 

 vincing evidence than we have at present. In the present dis- 

 cussion it sometimes happens that a group of faculae is considered 

 as identical with an earlier group seen two or three semi- 

 rotations earlier, when the same part of the sun has been seen 

 in the interval, but without showing the group, although the 

 district has been favourably presented for displaying faculae. In 

 such a case, and particularly if several semi-rotations have 

 elapsed, the two groups will be identified or not according to 

 the rotation period assumed ; so that if a single rotation period 

 for the whole sun be assumed in the preliminary reductions of 

 position for the sake of identification of the groups, there will be 

 an inevitable tendency towards a single rotation period in the 

 final result. 



The mean daily angular velocity given by the faculae is I4 16' 

 1 1"*3, corresponding to a sidereal period of 25d. 5I1. 28m. 12s., the 

 values for the northern and southern hemisphere, taken sepa- 

 rately, differing only by n"'5. It is worthy of note that this 

 corresponds to the rotation period of spots about latitude io°, as 

 given alike by Carrington and Spoerer's formulae, and that the two 

 zones 5° to 15 yield the greater number both of spots and faculae 

 which are available for these investigations. The present dis- 

 cussion, with whatever reserve its conclusions are to be accepted, 



