424 



NATURE 



[MarcA 6, 1879 



America, the effect of which has been to reduce prices and con- 

 sequently to impose a limit upon production. Several hundred 

 piculs of imitation Congou were shipped to London from Hiogo 

 in the course of last year, and are said to have been favourably 

 received in the market, both quality and flavour being of a high 

 order ; the only question remaining to be solved as to the success 

 of these teas is whether they "can be produced at prices low 

 enough to enable them to compete favourably in foreign markets 

 wit'h China and Assam teas." 



In the December part of the' Transuttfl of the Royal Academy 

 dei Lincei of Rome, Prof. Cossa gives an interesting account of 

 his researches on the occurrence of the three metals cerium, 

 didymium, and lanthanum. It appears that although these 

 metals occur always in but minute quantities, yet their occurrence 

 is far more frequent than is generally supposed, Prof. Cossa 

 having been able to trace them even in bones and in the ashes of 

 plants, not to speak of a number of minerals, such as certain 

 apatites, Carrara marble, scheelite, &c. In Carrara marble Prof. 

 Cossa found about two centigrammes of the mixed oxalates of 

 cerium, lanthanum, and didymium in every kilogramme of 

 marble ; there were also traces of yttrium. 



We have on our table the following works : — " The Ele- 

 ments cf Dynamics," second edition, James Blackie (Thin, 

 Edinburgh); "Simple Lessons in Domestic Economy," 

 Wm. Wyley Murly ; "Education as a Science," A. Bain 

 (Kegan Paul and Co.) ; "The Land of Midian," 2 vols., Capt. 

 Burton {Kegan Paul and Co.) ; " Reise aus den Stillen Ozean," 

 Max Buchner (J. N. Kerns); "The Study of Rocks," Text- 

 Books of Science, Frank Rutley (Longmans); "Dictionary 

 of Chemistry," vol. viii. part i, Henry Watts (Longmans) ; 

 " Report of the Recorder of the Botanical Locality Record 

 Club," West (Newman and Co.); "British Burma and its 

 People," Capt. Forbes (Murray) ; " Life in Asiatic Turkey," 

 E. J. Davis (Stanford); "Geological Survey of Victoria, 

 Report of Progress of the Secretary of Mines " (Triibner) ; " The 

 Two Voyages of the Pandora in 1875 and 1876," Sir Allen 

 Young (Stanford); "Practical Geology," W. J. Harrison (W. 

 Stewart and Co.); "Animal Physiology," Dr. A. Wilson (W. 

 and R. Chambers) ; "Manual of Practical Chemistr}'," A. W. 

 Blyth (Chas. Griffin and Co.) ; "A Ministry of Health," B. W. 

 Richardson (Chatto and Windus) ; "Morphology of Vertebrate 

 Animals," A. Macalister (Longmans and Co.); "The Colour 

 Sense," Grant Allen (Triibner); "Fuel, its Combustion and 

 Economy," T. Symes Prideaux (Lockwood) ; " The Evolution 

 of Man," 2 vols., Ernst Haeckel (Kegan Paul and Co.) ; "Ex- 

 perimental Culture of the Opium Poppy, " John Scott (Calcutta 

 Press) ; " Manual of Opium Husbandi-y," John Scott (Calcutta 

 Press) ; " Sewage Poisoning," Edward T. Blake (Hardwicke 

 and Bogue). 



The additions to the Zoological Society's Gardens during the 

 past week include a Common Hare {Lepus europcctis), British 

 Isles, presented by Mrs. F. Buckland ; an Impeyan Pheasant 

 {Lophophorits impeyanus) from the Himalayas, two Cheer 

 Pheasants {Phasianus ivallichii) from North India, received in 

 exchange ; a Nuthatch (^Sitta ccesia), British Isles, purchased ; a 

 Sambur Deer {Co-viis arisiotelis), bom in the Gardens. 



THE PHYSICAL NATURE OF THE SUN^ 



'T'HE riisstion whether all points of the sun are alike, in 

 ■*■ refeience to the emission of light and heat, is not yet 

 decided. As to the distribution of heat on the sun, many inves- 

 tigations have already been made w ith a view to answering this 

 important question. Ners'ander seems to have been the first to 

 discover (from temperature observations at Paris and Inns- 

 bruckj a temperature inequality of about J° R, which has 

 moreover the period of the sun's rotation (27 '25 days). Simul- 

 ^ By Dr. Gruss, in the A sironomisc/ie Nachrichteti: 



taneously. Dr. Buys Ballot made a similar inquiry in Utrecht. 

 Proceeding on the suppo.sition that a kind of h eat pole exists in 

 the sun, and that accordingly the rotation of the sun must appear 

 from long series of temperature detenninations, he got from ob- 

 servations of temperature at Harlem, Zwanenburg, and Danzig, 

 a period of 27 '682 days. Since this result differs so much from 

 that of Nervander, Buys Ballot subjected the calculations of 

 Nervander to a thorough scrutiny, from which he concluded 

 that that observer had ' ' not only taken the moon for the sun, 

 but had also mistaken the former." In his memoir Buys Ballot 

 further showed, that to the colder side of the sun, which was 

 presented to us on ist January, 1846, a temperature corresponded 

 that was, on an average, about 07° lower than that of the 

 wanner side, which was presented to us on 15th January 

 of that year. Carlini and D Arrest got nearly the same result 

 as Nervander. Airy, on the other hand, was imable to decide 

 from the Greenwich observations. Since by the distinguished 

 researches of Hornstein, Director of the observatory at 

 Prague, and of Broun, it has been proved that the time of 

 the sun's rotation may be deduced from variations of magnetic 

 and barometric phenomena more accurately and from a short 

 series (one year) of observations, and since both the period of 

 Nei-vander and that of Ballot differ so much from Spoerer's 

 and Carrington's rotation period, I submitted the Prague 

 temperature-observations for 1876 to a closer examination, 

 expecting a much shorter period from these than Hornstein got 

 from magnetic and barometric obserations, as I supposed 

 that it would correspond to the rotation, deduced from spot 

 observations, of the thermal equator of the sun, which, it is 

 known, does not coincide with the true equator. I worked the 

 observations therefore by the method given by Hornstein in the 

 Sitzmtgsberichte of the Vienna Academy (Bd. 67), as it is pecu- 

 liarly suited for such researches. I here communicate the final 

 result. The most probable value obtained for T was 25*56 days. 

 According to Carrington's obsei-vations, the position of the 

 thermal equator of the sun on the foregoing supposition would 

 have the latitude TO° to 20°, according to Spoerer's observations, 

 the latitude I 3° to 40°. As recent researches seem to show that 

 the influe nee of variation of the forces of the sun is reflected in 

 the variations^bf meteorological phenomena, I further investigated 

 the wind components of the year 1870, in their relation to the 

 rotation-time of the sun. For the east-west-components I found 

 a period of 267 1 days. Whether from this result may be con- 

 cluded a correspondence between prevalent winds in the sun, 

 such as Spoerer has deduced from his spot observations, will 

 have to be decided by closer investigation. 



THE STRUCTURE AND ORIGIN OF 

 LIMESTONES^ 



A FTER the obituary notices of eminent Fellows lost during 

 "^ the past year, who were more than usually numerous, the 

 president confined his own special address to the consideration 

 of the structure and origin of limestones, relying mainly on his 

 own observations, but incorporating general facts derived from 

 other sources. Since, in order to properly understand the nature 

 of the various constituent fragments of which many limestones 

 ai-e composed, it is necessary to know the organic and mineral 

 constitution of the various different living calcareous organisms, 

 this question was first considered from a somewhat novel point 

 of view, and they were regarded, not merely as living tissues, 

 but also as mineralised organisms, much attention being paid to 

 their special optical characters. Much attention had been also 

 paid to their true mineral constitution, so as to ascertain in 

 which groups the carbonate of lime exists in the form of calcite, 

 and in which as aragonite. The results are in some cases re- 

 markable, even in relation to biology, and are of great interest 

 and importance in the study of limestone rocks and their in- 

 cluded fossils, since subsequent changes depend mainly en 

 whether the original material was calcite or aragonite. This is 

 due to the fact that calcite is in a state of stable equilibrium, 

 and cannot be changed to aragonite, whereas aragonite is rela- 

 tively in a state of unstable equilibrium, can be changed to 

 calcite, and usually has so changed in limestone rocks. This 

 circumstance has given rise to a complete difference in the_ state 

 of preservation of many fossils. When they were originally 

 calcite, they may have been further consolidated, but retain their 

 original structure and optical properties, whereas when they 



' Abstract of AnniverEary Address to the Geological Society by Mr. H. C. 

 Sorby, F.R.S., President, communicated by the author. 



