136 



NA TURE 



[December 9, 1897 



to a matter of pure calculation. One thing is certain, till this 

 is done designs of large air-ships for the wholesale transport of 

 passengers, officers and cargo are not of the slightest value ; 

 their designers would do better to study mathematics, and help 

 in the heavy work of calculation still requiring to be done." 



For the purpose of testing whether change of chemical 

 structure ever results in change of weight, Landolt carried out 

 a number of experiments in the years 1890-92. Using a variety 

 of reactions, he made a careful series of weighings, both before 

 and after chemical combination, of substances sealed in glass 

 tubes, but the results were inconclusive. In three reactions 

 vvith silver sulphate and ferrous sulphate, producing silver and 

 ferric sulphate, the apparent loss of weight was, on the average, 

 more than nine times as great as the probable error of weighing, 

 and a similar apparent loss was indicated as the result of six 

 reactions between iodic acid and hydriodic acid. In some other 

 reactions, however, the observed change of weight was some- 

 times positive and sometimes negative. A similar set of weigh- 

 ings for another silver reaction closely related to the one used 

 by Landolt have now been made by Fernando Sanford and 

 Lilian E. Ray, and are described in the Physical Review 

 (October). The reaction used was the reduction of silver from 

 an ammonia solution of the oxide, by means of grape sugar. 

 The weighings show greater irregularities than those of Landolt, 

 but they are still accurate enough to justify the authors' con- 

 clusion that the reaction used by them was unaccompanied by 

 any such change of weight as was observed in the similar 

 reaction studied by Landolt. 



The September number of Terrestrial Magnetism^ the pub- 

 lication of which has been unavoidably delayed, contains, among 

 other contributions, a paper " Ueber die Fehler bei Erdmag- 

 netischen Messungen," by H. Wild, and a translation of Prof. 

 Max Eschenhagen's paper " On Minute, Rapid, Periodic Changes 

 of the Earth's Magnetism," already noted in Nature, 



A COPY of an inaugural address on "Advances in Biological 

 Science during the Victorian Era," recently delivered by Mr. 

 Isaac C. Thompson as president of the Liverpool Biological 

 Society, has been sent to us. The address is an instructive 

 review of the most prominent biological work of the past sixty 

 years, and the nature of it shows that the Liverpool Biological 

 Society ranks high among the scientific bodies of the city. 



Mr. Alfred Harker's excellent little guide to the study 

 of rocks in thin slices under the microscope, published under 

 the title "Petrology for Students" by the Cambridge Univer- 

 sity Press, has reached a second edition. The book has been 

 revised throughout, and more attention has been given to 

 American examples, at least among the igneous rocks. No 

 better introduction to the study of petrology could be desired 

 than is afforded by Mr. Harker's volume. 



The Essex Field Club will publish about Christmas, as one 

 of their "Special Memoirs," a volume on the " Mammals, 

 Reptiles and Fishes of Essex," by Dr. Henry Laver, one of 

 the Vice-Presidents of the Society. Taken in conjunction with 

 Christy's "Birds of Essex," issued by the Club in 1 891, it will 

 afford a complete guide to the vertebrate fauna of the county. 

 The work will be illustrated by original drawings by Major 

 Bale, of Colchester, and Mr. H. A. Cole, of Buckhurst Hill, 

 depicting some of the more interesting species and their haunts 

 in the county. 



The magnetic observations made at 509 places in Asia and 

 Europe during the period 1867-1894, by Dr. H. Fritsche, 

 Emeritus Director of the Russian Observatory at Pekin, have 

 been brought together and published as a pamphlet in which 

 the whole of the MS. is reproduced in facsimile. The first 



NO. 1467, VOL. 57] 



part of the pamphlet deals with the formulas used in the cal- 

 culation of horizontal intensity, and following it are tables 

 showing the magnetic elements at 509 places in Europe, 

 Siberia, and China, the longitudes and latitudes of the places 

 being given, and also the dates of observation. Magnetic 

 anomalies are discussed, and two local anomalies — one near 

 the island of loussar-oe in Finland, and another near Moscow, 

 are described in detail, and illustrated by three maps. 



With reference to the note on p. 59 of our issue of November 

 18, as to the storm signals used by various maritime countries, 

 which was based upon information contained in the U.S. Pilot 

 Chart of the Pacific Ocean for November, we have received a 

 note from Admiral Capello pointing out that, in addition to the 

 use of flags of the Commercial Code and occasional semaphoric 

 signals for the purpose of giving notice of the state of the 

 weather between theaBay of Biscay, Madeira and Gibraltar, to 

 passing vessels that may require it, the drum and cone signals 

 adopted by the late Admiral FitzRoy are regularly hoisted at 

 the semaphores to notify the probable approach of stormy 

 weather. 



The additions to the Zoological Society's Gardens during the 

 past week include a Black-handed Spider Monkey {Ateles 

 geoffroyi, ? ) from Central America, presented by Mr. F. Colsell ; 

 two White-naped Weasels {Pacilogale albimuha) from South 

 Africa, presented by Mr. W. Champion ; two Flat-backed 

 Terrapins ( Cyclemmys platynota) from Johore, Malay Peninsula, 

 presented by Mr. S. S. Flower; two Chameleons ( C-^aw^/iJ^w 

 vulgaris) from North Africa, presented by Mr. Horace Dibley ; 

 two Ring-tailed Coatis {Nasua rufa), a Kinkajou {Cercoleptes 

 caudivolvubis), a Punctated Agouti {Dasyproda piinclaia), a 

 Globose Curassow {Crax globicera) from British Honduras ; two 

 Vervet Monkeys {Cercopithecus lalandii, S ? ) from South 

 Africa, deposited ; two Scaup Ducks {Fuligula marila, (J ? ), 

 European, purchased. 



Dr. C. B<!)RGEN asks us to state that in his letter on "The 

 Law of Divisibility," which appeared in Nature of Novem- 

 ber 18 (p. 54), he should have written 2(ai,_|.a-i instead of 

 5(a7/-a-|-i. 



OUR AS TRONOMICAL COL UMN. 



Meteors (Geminids). — The interest awakened by the recent 

 expectation of a brilliant return of the Leonid meteors may induce 

 many to make observations of other showers. It may be well, 

 therefore, to remember that from the 9th to the 12th inst. the fairly 

 good shower of the Geminids takes place. The radiant point 

 is situated near Castor in R.A. 7h. and north declination 32°. 

 In the years 1885 and 1892 there were remarkably good displays. 



o Ceti (Mira). — In this column last week reference was 

 made to the brightness of " Mira " near its maximum. Further 

 observations made at the Solar Physics Observatory, South 

 Kensington, show that, as at previous times, the light curve of 

 this star is subject to fluctuations near maximum, but the star 

 is still about the third magnitude, being considerably brighter 

 than 7 Ceti (3*38 N.O.U.). Only visual observations of the 

 spectrum have been possible in consequence of the troubled state 

 of the weather, which has not allowed of the long exposures 

 necessary to secure the violet portion of the spectrum ; the 

 visual observations show the same bands as recorded by Sir 

 Norman Lockyer at Westgate in 1888 (Nature, vol. xxxviii. 

 p. 61). This year the star will be well situated for observation 

 for a considerable time after its brightest period, before being 

 lost in the twilight, as it is now on the meridian about 9.30 

 p.m. We hope later to be able to give some additional facts as 

 to the change which takes place in the invisible portion of the 

 spectrum in passing from maximum to minimum. 



The Companion of Sirius. — Prof. Burnham, using the 

 36-inch Lick refractor, was the last to observe the companion of 

 Sirius before its perihelion passage. The observation was by no 



