KNOWI.I.Df.l 



Jam'akv. t'»|j. 



I. Kc. D. 2i" 4" 59"' 19*; I. Tr. 1. 24"' 3" 21"", I Sh. K. 4" l'*'". 



I. Tr. K. 5" 34"': I. Oc. K. 2.V' 2" 53"; II. Tr. I. 2(.'* 4" 52'", 



II. Sh. K. 4'' S'*"". The abovt* arc all in the inorniiiK hours ; 

 pheiioiiifiia separated by coiiiinas arc all on the same day. 

 Kclipsesucciir hit;h left of the disc in the inverted iinage, lakiiiK 

 the direcliiin of the belts as hori/nnlal. IV. does not imdcrRo 

 eclipse at present. 



Sa riKN is approachiliK the Sun. but still easily observable. 

 I"<|iiatorial diameter IS". Major axis of riii); 41". minor 15". 

 The folliiwitiK Table nives ICast elonj;.ili()iis of Satellites. To 

 liiid intcriiu'diate ones appiv multiples of l** 2l'' for Tethys. 

 2" l,s" for I>ione, 4" 12. J" forKhea. 



Tethvs Keb. 1" ll" c ; 7'' 3" c : U" 7" m ; US'" 1 1" f : 

 24'' 3'' c : 28'' 9'' III. Dioiie leb. l-" 5'' c ; 7'' 5'' ;;/ : 12'' 4'' c : 

 18'" 4'' in: 2i'' 3" c : 29'' 3" m. Khea l-eb. 1'' ;/oo/i : 

 lOJ ]i. ^.. ig.i 2" c; 28'' 3"f. For Titan and lapctns E., W., 

 denote East and West KlonKations, I.S. Inferior and Superior 

 Conjunctions. Titan Keb. 2'' S" in 1. fi"" 4'' in W, 10'' 2'' in S. 

 14'' (•,'' in E, 18'' 7'' in I, 22'' 4'' in W. 26'' 2" in S; March 

 1'' r.'' in ]■:. lapetus Feb. 5'' 8'' ;/( W, 24'' n'' c S. 



L' KAN IS remains invisible. 



Niit'Tl'Nli is very well placed in (lemini. The map given 

 last month is still available for lindinfi it. 



CoMLTS. — Fphemerides for three comets in February were 

 t;iven last month. Prolonged observation of (Jnenisset's coitict 

 is desirable, as it may possibly be identical with 1790, III. 



MliTliORS. — Mr. W. F. Denning gives the following showers. 



Minima 

 I'' 10'' ni. 



)!• Al.Gol..— Feb. l-* 3'' c. 10' 5" in. IS-" 7" c, 

 Period 2* 20'' 49'". Every 3rd mitiiiiiiiiii given. 



Clusters and Nebulae. 



.M.A1"11HM.\T1C.S AM) I'lIV.SIC.S IX Till: i:XCVL Lol'AKlJl.V 



llRriWXXKA. 



Tm; eleventh edition of the " Encyclopaedia Hritannica " is 

 of a vintage, which, judging from the initials of the contributors 

 of its articles on mathematical and physical subjects, needs a 

 bush no more than the ninth edition. Hush or no bush, such 

 a production cannot pass unnoticed, though to discuss 

 adequately even one group of articles is beyond the powers 

 of this reviewer, even if the attempt were not beyond the 

 scope of this journal. 



Mathematics and physics have always been special features 

 of this work, and in the present edition the compilers have 

 kept this fact in mind. There is not in English, as there is 

 in I'rench and German, a Dictionary or ICncyclopacdi.i of 

 Mathematics, and the eleventh edition of the "' Encyclopaedia 

 Britaimica " aims definitely at supplying this need. This 

 means that a large number of new articles have been written, 

 while a few of the older articles re-appear. Among these, of 

 course, we find treatises by such men as Cayley and Tait, 

 which have become in a measure classical. On the other 

 hand we have our attention called to the modern trend of 

 mathematical thought by the new article " Mathematics." 

 This, contributed by A. N. Whitehead, takes the pUice of 

 ProfessorChrystal'sarticle. The sameauthonwith Mr. Bertrand 

 Russell, contributes sections under the heading " Geometry," 

 an article which combinesold and new. ProfessorO. Heiirici dis- 

 cusses Euclidean. Prospective, and Descriptive Geometry, while 

 Cayley"s Analytical Geometry has been revised by Professor 

 E. H. Elliott. .-Vmoiig other contributors in Pure Geometry we 

 notice the names of 1-2. W. Hobson, A. E. H. Love and 

 H. F. Baker. In Applied Mathematics Professor H. Lamb. Sir 

 George (ireenhill, and Sir George Darwin, are noteworthy 

 contributors. Physical Science moves so fast now-a-days 

 that a treatise may become out of date in the course of its 

 preparation for the press. We refer, of course, more particu- 

 larly to the rapid growth of the new study of radio-activity. 

 But the new views on the structme of matter are bound to 

 have their cfTect in all branches of Physics. In the eleventh 

 edition the group of .irlicles of which the Properties of Matter 



and the .Aether form the theme are particularly noteworthy. 

 Part of Clerk Maxwell's famous article " .Atom " can never be 

 out of date, and reappear imder the heading "" Molecule." 

 The present occupant of Maxwell's chair. Sir J. J. Thomson, 

 contributes a new article " Matter." Sir Joseph Larmor's 

 " .Aether " contains all that was valuable in .Maxwell's 

 " Ether " modified in accordance with the prevident views. 



More of Maxwell's distinctive work reappears in Lord 

 Kayleigh's "Capillary .Action" and Professor G. H. Bryan's 

 " Diffusion." Lord Kelvin, the last survivor of the great 

 " Early Victorian " group of Cambridge Physicists, contri- 

 buted two famous articles to the ninth edition : "Elasticity" 

 and " Heat." He survived long enough to be consulted with 

 regard to these, and there can be no question that in handing 

 over to Professors .A. E. H. Love and H. L. Callendar the 

 task of bringing them up to date, he made an admirable 

 choice. In the region of "' Light" Lord Kayleigh is fortunately 

 still with us. and his new articles on " Diftraction" and "Inter- 

 ference." both of them experimental as well as mathematical, 

 take the place of his former "Wave Theory" and Professor 

 Tail's '■ Light." The remarkable advance in optical instru- 

 ments due to the work of Abbe and Schott finds recognition ; 

 and articles on "Lens" and ".Aberration" have been con- 

 tributed by members of Zeiss' staff at Jena. 



In Electricity and Magnetism a noteworthy transformation 

 has been made. Professor G. Chrystal. of Edinburgh, taken 

 by death from his work since these p.ages came into the 

 reviewer's hands, was the author of the articles in the ninth 

 edition, which were regarded as the best existing text-book of 

 the " eighties." In their place we now find a series of articles 

 by Professor J. A. Fleming, Sir J. J. Thomson and others, 

 which are as far as possible up-to-date, and which by their 

 headings and arrangement simplify the process of reference. 

 As an example of the difficulty of keeping abreast of the times 

 in such a work as this the reviewer may mention that he has 

 been unable to find either under the heading " Compass " or 

 " Gyrostat " any reference to the Gyrostatic Compass. 



