474 



NATURE 



[M^ARCH 19, 1896 



science of number and magnitude," "the science which treats 

 of the propertie and relations of quantities," or more briefly, 

 "the science of quantity." Occasional definitions of a more 

 comprehensive character are to be found scattered here and 

 there iti mathematical and other writings, but Mr. Kempe 

 doubts whether any of them would satisfy a large body of 

 modern mathematicians ; therefore he suggests the following as a 

 provisional definition: " Mathematics is the science by which 

 we investigate those characteristics of any subject-matter of 

 thought which are due to the conception that it consists of a 

 number of dift'ering and non-differing individuals and pluralities." 

 Perhaps this definition will provoke some one to formulate 

 another. 



The playgrounds of our public schools are said to be the 

 arenas in which British battles are fought ; and, in a similar 

 sense, we may say that the scientific societies of our colleges 

 are the training schools of scientific investigators. The system 

 of compulsory games tends greatly to limit the time which 

 public schoolboys can devote to natural history or other 

 research, but a few enthusiasts contrive to gratify their curiosity 

 to know something about natural facts and things. The 

 twelfth annual report of the Felsted School Scientific Society 

 testifies to the existence of this spirit of inquiry. Among the 

 papers it contains, we notice one on " The Geology of Felsted," 

 by Mr. J. French, and another on " Recent and Proposed 

 Arctic Exploration," by Mr. J. F. Hartin. The Society used 

 only to be concerned with natural science, but its field of 

 operations has been enlarged, and its usefulness increased, by 

 the creation of a Chemical Section. Stern methods are taken to 

 keep up the attendances at the meetings, for we read : " That 

 any member failing to attend at least one ordinary general meet- 

 ing in each term in which such meetings are held, without 

 reasonable excuse, be liable to ejection from the Society." It 

 is appalling to think what would be the result of the application 

 of this, rule to many learned societies. 



A LARCE number of students, as well as persons who do not 

 pretend to possess any special scientific culture, will be glad to 

 know that Tyndall's "Glaciers of the Alps" (Longmans, 

 Green, and Co. ), first published nearly six-and-thirty years ago, 

 and for a long time out of print, has been reprinted. Upon 

 Lord Kelvin's advice, no changes have been made in the contro- 

 versial portions of the book, so the text has been left practically 

 unaltered. Messrs. Kegan Paul and Co. have published a 

 popular edition of Sir John Lubbock's standard work on 

 " Seedlings," reviewed in these columns in January 1893 

 (vol. xlvii. p. 243). The parts included in the new volume are 

 those of most general interest, and 282 of the 684 illustrations 

 in the original work are used to elucidate the text. A new 

 edition has been published of " Griffin's Electrical Engineers' 

 Price-Book," edited by Mr. H. J. Dowsing. Nearly seventy 

 pages of new matter have been added, and the whole of the 

 prices have been brought up to date. Electrical and other 

 engineers and contractors know that the volume is a ready and 

 trustworthy means of reference to the prices with which they 

 have to deal. The new and improved edition of " Historical* 

 and Future Eclipses," by the Rev. S. J. Johnson, just published 

 by Messrs. James Parker and Co., will be appreciated as fully 

 as the original little volume, which came out twenty-one years 

 ago. The book is extremely handy, and contains not only a 

 vast amount of interesting information with regard to eclipses 

 of past and future time, but also notes on planets, double stars, 

 and other celestial matters, thus making it valuable to practical 

 astronomers. 



The additions to the Zoological Society's Gardens during the 

 past week include a Campbell's Monkey (Cercojiiikecus camp- 

 belH, (J ) from West Africa, presented by Miss Lilian Frost ; 

 NO. 1377, VOL. 53] 



two Black-backed Jackals {Canis mesomelas), a Puff Adder 

 ( Vipera arietans) from South Africa, presented by Mr. J. E. 

 Matcham ; a Condor (Sarcorhamptts gryphtts) from South 

 America, presented by Mr. C. J. Wedderburn ; a Guillemot 

 {Loinvia troile), British, presented by Mr. J. L. Palmer ; a 

 Moorish Tortoise {Tesludo matiritanica), from North Africa, 

 presented by Mrs. Powell ; a White-crowned Mangabey (^Cerco- 

 cehtts athiops, ? ) from West Africa, an Isabelline Lynx [Felis 

 isabellina, 6 ) from Ladakh, Cashmere, deposited ; a Maguari 

 Stork {Dissura maguari), a Guira CucVoo [Guira piririgua), a 

 Burrowing Owl (Speotyto ciinictdaria), a Brown Milvago 

 {Mihmgo chimango), a Condor {Sarcorhamphus grypht(s), a Boa 

 {Boa constrictor) from South America, six Mexican Quails 

 (Callipepla squainata) from Mexico, a Scarlet Tanager {Raiii- 

 phoc(?lus brasilius), three Scarlet Ibises (Etidociintis ruber) from 

 Para, a Ruff (Machates pugnax), two Redshanks ( Totantts 

 calidris), British, purchased. 



OUR ASTRONOMICAL COLUMN. 



Variable Star Clusters.— The recent announcement by 

 Prof. Pickering, of the discovery of variability in a large number 

 of stars forming parts of star clusters (Nature, vol. liii. p. 91), 

 has led Dr. Belopolsky to examine some of the photographs of 

 clusters taken at Pulkowa. Two photographs of the cluster 

 M3 (N.G.C. 5272), in Canes Venatici, were taken in March 

 1894, and two more in April 1895. I" t^^e later photo- 

 graphs one sar was found to be two magnitudes brighter thar> 

 in 1894, anddifferences of brightness can also be traced in the 

 case of other stars among the 1800 shown upon the photographs 

 {Ast. Nach., 3338). The Arequipa negatives of the same cluster 

 indicated a variation of brightness in eighty-seven stars, 

 amounting in some cases to at least two magnitudes. 



The Spots on Saturn.— The inability of Prof. Barnard 

 to detect any spots on Saturn with the aid of the Lick telescope 

 may possibly have thrown some doubt upon the existence of 

 such spots. Nevertheless, the observations of them by Mr. 

 Stanley Williams have 'given such remarkably consistent results, 

 that it is difficult to believe them illusory. In a recent' 

 article {Observatory, March, p. 112) Mr. Williams points 

 out that there has been some misconception as to the 

 nature of the Saturnian spots and the conditions for their 

 satisfactory observation. While generally admitting the 

 superiority of large telescopes, Mr. Williams holds that 

 the spots on Saturn are such as to require a sight specially 

 trained for their observation. The characteristics of the spots 

 are (i) considerable size, (2) faintness, (3) extreme indefinite- 

 ness. The bright equatorial spots average about 2" in diameter, 

 while the dark spots on the broad double belt in the northern 

 hemisphere have sometimes appeared as large as 4" long by 2" 

 or 3" broad. Similar spots have been noted by other observers, 

 and the estimated positions have been sufficiently accordant to 

 make it probable that the same objects were observed. 



The planet will be in opposition on May 5, and it is to be 

 hoped that the spots will receive the attention of observers. The 

 spots appear to be best seen with low powers ; with a power 

 of 140 an equatorial spot has been observed to shine with almost 

 stellar brightness, but with higher powers this peculiar bril- 

 liancy disappeared. Another point in Mr. Williams' experience 

 is worth putting on record, namely, that in the south of 

 England, at least, definition is usually much better about the 

 time of sunset and for an hour afterwards than at other times. 



Computation of the Times ok Solar Eclipses and Oc- 

 cultations. — In the Kevista do Observatorio (Rio de Janeiro) 

 for 1886, an account was given of a graphical method by which 

 the approximate times of occurrences of solar eclipses and oc- 

 cultations, sufficiently accurate for first approximations, could be 

 determined. Three years later, in a subsequent Revista, an 

 application of this method to the eclipse of the sun of December 

 22, 1889, was made by Mr. Morize, of the Observatory of Rio. 

 With the idea of making this method more general and ap- 

 plicable for all latitudes, the Director of the Observatory, Mr. 

 L. Cruls, has published a short account of the method, simplified 

 both as regards the computations and the graphical construction. 

 The principle is based on the parallactic displacement of the 

 moon in right ascension and polar distance., the values of which 



