Feb. 2, 1883.] 



• KNOWLEDGE • 



75 



the different metals when used as conductors, and the 

 etKciency of the different materials used for insulating pur- 

 poses, are exhaustively dealt with ; several other important 

 ijuestions being also considered. The adaptation of 

 asbestos is referred to, but little is said about it, owing, 

 doubtless, to the short experience so far olitained. It 

 is, however, suggested, and we think rightly, that 

 there appears to be a promising field for it The 

 authors, speaking of the manufacture of carbons, assert 

 tliat " to give precise details of the mode of pro- 

 ducing carbons, followed now by some of the principal 

 makers, is out of the question, as the secret, if there bo 

 one, is jealously kept" A history is then given of the 

 known processes, taken from M. Fontaine's " L'Eclairage 

 Electrique," demonstrating how far in this branch of the 

 subject the pioneers of electric lighting had advanced. So 

 much, in fact, do they appear to have accomplished, that 

 one marvels at the comparatively small progress since 

 made. M. Carre, who may be regarded as one of the, if 

 not the, principal manufacturer of electric carbons, has 

 conducted a large number of experiments, and has been 

 enabled by these means to deduce several important facts, 

 of which he takes advantage in the process of manufacture. 

 Referring to the Jablochkoff candle, we are informed that 

 a foreman, storekeeper, and twenty-nine men are capable 

 of producing an output of 5,000 candles per day, or 

 1,800,000 per annum. 



Section 4 contains descriptions of the various forms 

 of arc, semi- incandescent, and incandescent lamps. As in 

 the other sections, an historical sketch precedes the de- 

 scription of the various modem forms, implying thereby a 

 considerable expenditure of time and trouble. It is with 

 great satisfaction that we find honour awarded to those to 

 whom, in our opinion, it is justly due. " To whom in future 

 years," says the writer, " will the honour of this revolution 

 (in the application of electricity to lighting) lie accorded ] 

 To no one person, certainly, but amongst the crowd of 

 -scientific workers, it is evident that a first place must be 

 accorded to il. Gramme and M. Jablochkoff." The descrip- 

 tion of Edison's work is naturally a most important feature 

 in the chapter on incandescent lamps, and a highly interest- 

 ing account is given of the different phases in the history 

 of his multitudinous patents. Edison's meters for measur- 

 ing the amount of current supplied are fully described, 

 and then follows a very elaViorate statement of the claims 

 of Edison and Swan to priority, an effort being made to 

 demonstrate that Swan was first in the field, and more im- 

 portant still, that one of the chief claims of each of these 

 two heroes (if we may be permitted so to style them) are 

 absolutely diametrical, and neither of them essential. This 

 closing section is certainly not the least interesting, and 

 the book is completed by an extensive appendix, comprising 

 abstracts of patents, kc. 



The work is splendidly finished, printed in good clear 

 type, on firstclass paper, and contains upwards of eight 

 hundred magnificent illustrations, such as we rarely see in 

 English manuals. It teems with most valuable infor- 

 mation to all who are interested in the subject, and it 

 would be difficult to imagine a treatise of a more 

 exhaustive and entertaining character. It appears at a 

 most opportune moment, and will certainly do a gi-eat deal 

 towards dispelling the doubts and ditficulties of many 

 engineers and others who will soon, if they do not already, 

 perceive the necessity of possessing a knowledge of the 

 principles and applications of the youngest of the sciences. 

 A second volume is promised, and we look forward to it 

 with considerable interest, anticipating that the two 

 v^olumes will together constitute a standard manual of the 

 highest order. 



THE FACE OF THE SKY 

 From Febeuary Sxn to Febrdaby 16th. 



THE Bun should be examined on every clear day for spots and 

 facnlir. 



Mercury is invisible. Venus, though very low down, ia still a 

 conspicuous object before sunrise. 



The con.stellations now visible (see " Tlie Stars in their Seasons," 

 Map II.) are Taurus, Gemini, Cancer, Leo, Orion, Monoceros, 

 Pegasus, and Cetns, setting in the S.W. and W. ; and Ljtsi and 

 Cygnas doing the same in the X. and N.W. ; Andromeda in the 

 West too ; Coma Bei'eniees, Canes Venatici, and Bootes in the E. 

 and X.E. ; and Ursa Major to the E. of the zenith. 



Saturn should be looked for as soon after dusk as possible, as he is 

 rapidly approaching the west. He is still to be found to the S. and 

 a little to the E. of Arietis. Jupiter is still the most conspicuous 

 object in the night sky. He scarcely moves from his position to 

 the W. and a little to the X. of J Tauri. His angular diameter is 

 slowly diminishing, but this can hardly be detected without micro- 

 metrical measurement. The phenomena exhibited by his satellites, 

 and visible at fairly convenient hours, are somewhat numerous 

 during the next fourteen days. To-night (2nd) Satellite 11. will 

 be occulted at 7 h. Sm., not to reappear from eclipse until 

 11 h. 52m. 4s. p.m.; nine minutes after midnight Satellite I. will 

 enter on to Jupiter's face ; the usual sequence of phenomena of it 

 and its shadow happening during the earlier hours to-morrow 

 morning. On the 3rd, Satellite I. will be occulted at h. 19 m. 

 p.m., and reappear from eclipse at 12 h. 35 m. 7s. p.m. The egress 

 of the shadow of Satellite II. will happen at C h 19m. p.m. on the 

 4th. This will be followed by the ingress of Satellite I. at U h. 36 m. 

 At 7 h. 39m. the shadow of Satellite I. will follow it on to 

 Jupiter's face. Satellite I. itself will pass off at 8h. 51m., and its 

 shadow at 9 h. 55 m. On the 5th, Satellite I. will reappear from 

 eclipse at 7h. 4 m. 5 s. The transit of Satellite III. will begin 

 at 10 h. 58 m. p.m., and its egress happens at 1 h. 39m. a.m. on the 

 Uth. This should be carefully watched, for the rea.son given on 

 page -12. On the 9th, Satellite III. will reappear from eclipse at 

 7 h. 52 m. 23 s. p.m., and Satellite II. will be occulted at 9h. 32m. 

 An occultation of Satellite I. will happen at 11 h. 9 m. p.m. on the 

 10th. On the 11th the shadow of Satellite II. will enter on Jupiter's 

 disc at 6 h. 11m. p.m. ; at 6 h. 41 m. the Satellite itself will pass 

 off the opposite limb. The ingress of Satellite I. will occur at 

 ,S h. 2() m., and the shadow of Satellite II. will leave Jupiter's face 

 at 8 h. 57 m. The shadow of Satellite I. will begin to cross his disc 

 at 9 h. 34 m. ; the Satellite will pass off at 10 h. 41 m., followed by 

 its shadow at 11 h. 50 m. On the 12th, 1. will reappear from 

 eclipse at 8 h. 59 m. 45 s. The egress of the shadow of this same 

 Satellite will happen at 6h. 19 m. p.m. on the 13th. If the student 

 will sit up until the constellation Leo is well above the horizon, he 

 may now obtain a telescopic view of the planet Uranus. As a 

 guide to its position, he may draw a line from r Leonis through 

 a 6th magnitude star (89) to the left of it (" The Stars in their 

 Seasons" Map II.), nearly on which line, and to the left of 89 

 again will be found the planet. It will be recognised at once by its 

 pale bine disc, which will become more and more perceptibly 

 marked with each increase of magnifying power. 



The Moon does not rise until nearly .3 a.m. on the 2nd ; and 

 scarcely comes into view for the observer's purpose until the 9th, 

 at noon, on which day she is 17 days old. On the 9th she travels 

 from Aquarius into Pisces. She remains in Pisces during the whole 

 of the 10th and 11th, passing on the 12th into Aries, out of which 

 she does not pass until the 1-tth, when she moves into Taurus. She 

 enters her first quarter at 9h. 55m. a.m. on this day. She does not 

 quit Taurus during the 15th. The solitary occultation visible dur- 

 ing the date comprised in our heading is that of the 5J mag. star 

 liAC, which disappears at the moon's dark limb, at an angle of 

 143° from her vertex,* at lOh. 5m. p.m., and reappears at her bright 

 limb at llh. 10m. p.m., at an angle of 288° from her vertex. 



HEALTn oY Bkightox. — According to the Registrar- General's 

 report for the week ending Saturday last, Brighton occupies a con- 

 spicuously favourable position in the list of the twenty-eight large 

 towns whose rates of mortality are periodically published. It 

 comes first on the roll, with the very low mortality of 127 per 

 1,100 i)er annum, having a note appended that no death during 

 the week was referable to any of the principal zymotic diseases. 

 Leicester and Bristol follow Brighton, with rates of IC'l and 16'4 

 respectively, while Hull, Sunderland, and Liverpool, at the other 

 end of the list, present the formidable figures of 305, 306, and 

 31-1. The average mortality of the twenty-eight towns during the 

 week was 224. — Daily Telegraph. 



* See page 11. 



