Dec. 1, 1882.] 



KNOWLEDGE ♦ 



437 



the little " Griscom," nor could we imagine it possible for 

 a chapter to be -nritten on " Electric Railways " which 

 ignores the well-known labours of Edison. These and other 

 deficiencies, coupled with an excessi^ e attention to intro- 

 ductory matter, which, from the smallness of the book, is 

 unwarrantable, detract considerably from the value of what 

 might, and indeed ought, to have been a most useful work. 

 The illustrations are far too few for the subject, the first 

 appearing on p. 29. 



Anent the language, it is noticeable for what may be 

 styled its angularity ; and the author would have been 

 amply repaid for any extra care he might have bestowed in 

 striving to make it more palatable and smooth. A certain 

 laxity of expression is also to be observed in places ; thus, 

 we read on p. 20, that the " current is generally «ss'u«e(^ 

 lo arisp at the surface of the zinc plate, which therffore 

 begins to dissolve."* For those, however, who know 

 something of the science of electricity, but little of its 

 application, there is plenty of profitable reading to be 

 found in the little book before us. To such we can 

 recommend it. 



A Vessel Struck by Lightning. — During a severe 

 thunderstorm which burst over Glasgow last Friday 

 evening, the lightning struck the mizen-mast of the steamer 

 Prussian at Go van, killing one man and injuring four 

 others. 



A. C, who has tried it, is authority for the following : — 

 Take one-fourth cup of strong vinegar, crumb finely into it 

 some bread. iLet stand half-an-hour, or until it softens into 

 a good poultice. Then apply, on retiring at night. In the 

 morning the soreness will be gone, and the corn can be 

 picked out. If the corn is a very obstinate one, it may 

 require two or more applications to effect a cure. — Scien- 

 tific American. 



BuBDENS UPON COMMERCE. — " It is asserted," says the 

 Nmo York Herald, " that there is no other port in the 

 world where a ship, from the hour she enters to the hour 

 she leaves it, is taxed so heavily as here in New York. 

 As soon as a vessel appears off Sandy Hook the system of 

 legalised piracy begins. Every knot she makes brings on 

 board a different set of harpies, and they cannot be driven 

 oft' until their exorbitant demands have been satisfied. 

 When her anchor is cast, she is invaded by a fresh detach- 

 ment of uniformed toll-gatherers, and still later, when she 

 hauls up to one of the so-called wharves, another gang of 

 officials is promptly on hand with a money demand which 

 must be satisfied, under the pains and penalties of confisca- 

 tion. The Chamber of Commerce has at last undertaken in 

 earnest a reform of this legalised system of blackmail. The 

 question is one of the highest importance, and we hope 

 that this representative commercial body of the city, tlio 

 State, and the countrj-, will not allow the subject to drop 

 until it has worked out a remedy. Our whole shipping 

 industry is outrageously taxed and oppressed. We have 

 in the body of our laws — federal, State, and municipal — 

 protection for everybody and everything except the un- 

 fortunate o^vner of a ship and the crew who sail her. The 

 exactions of the Barbary pirates were hardly more oppres- 

 sive than those now demanded by the port officers of New 

 York. Tlie legal fees eat up nearly all the profits of a 

 voyage, no matter how successful. The extortion is so 

 great, that it is almost a wonder we have any commerce 

 at all." 



The italics are < 



letters to tfte ®liitor, 



\T\e Editor doea not hold himself responsible /(»• the opinions of his correspondents. 

 He cannot undertake to return mhnutcripis or to correspond tcith their vrtters. AU 

 communications should be as short as possible^ consistently Kith full and clear state- 

 ments of the Kriter's meaning.] 



All Editorial communications should he addressed to the Editor of Knowlbdgb : 

 all Business communications to the Publishers, at the Office, 74, Great Qufea- 

 ttreet, W.C. 



All Semiffanees, Cheques, and Fost-Office Orders should be made payable to 

 Messrs. Wtfman ^ Sons. 



*,• All letters to the Editor vill be Ifumlered. For convenience of reference. 



eorrespojidents, ichen referring to any letter, will oblige by : ' 



and the page on tchich it appears. 



" In knowledge, that man onlv i 



etate ot fransitiot. Nc 



than fixity of opinion." — Faraday. 



" Show'me a man who makes no 

 ■done nothing." — Liebig. 



mistakes, and I will show you a man who has 



[640] — You lately suggested that the dark side of the new moon 

 should be watched to see whether the rim of light was brightest 

 at the equator, the object being to detect increased atmospheric 

 refraction where the sun's rays had been most powerful for the 

 previous fortnight. 



Last evening the new moon was above the horizon long enough 

 after sunset for f a votu-able observation, and I think the atmospheric 

 conditions here enabled me to see the dark part with more distinct- 

 ness than it is ever seen in England. To the naked eye the rim of 

 light was very vivid, the irradiation effect on the illuminated side 

 most remarkable, so that the dark moon looked like an acorn in its 

 cup, the bright crescent being so distinctly larger; and the 

 greatest intensity of illumination along the dark rim seemed con- 

 centrated near the southern cusp. 



Getting out my telescope, a Dollond's "Student" (3 in.), new 

 effects were observable. The dark side was so bright that, keeping 

 the illuminated crescent out of the field, I could identify most of 

 the larger objects on its surface. The Mare Humorum was as 

 plainly distinguishable as in the map attached to your moon book 

 and to Mr. Webb's book. The dark spot numbered 272 (Grimaldi) 

 was equally plain. A distinctly luminous spot was noticeable, jnst 

 corresponding, I thought, to the position of "La Hire" in the map, 

 and I could have picked out a quantity of other detail. 



But the most important fact observable seemed to me the 

 character of the illumination of the " dark "Tim. In the telescope, 

 that which appeared to the naked eye as light shining round the 

 orb was plainly visible as simply the bright higher surface lying 

 along that limb of the moon seen in contrast to the great expanse 

 of grey plains covering the dark surface (or, let me say, the half- 

 lighted surface, for it is ridiculous to describe it as dark) from the 

 Mare Humorum down nearly to the northern pole. And the 

 apparent extra illumination of the rim near the southern cusji was 

 intelligible at a glance in the telescope. A great quantity of high 

 land brightness laps over the moon at that part, the grey plain 

 Ij'ing further back. In the telescope no greater brightness was 

 observable near the rim, at 276 for example, than on the surface 

 at 188. 



A bright star in Libra, Iota, or Zcta, I think (or was it Alpha ?), 

 was prettily occulted while I was watching all this a little before 

 eight e' clock, and nothing could have been more instantaneous than 

 its disappearance. A. P. S. 



Simla, India, net. 16. 



ARC ON LUNAR DISC. 

 [041] — Yesterday (the T7th) I happened to look at the moos 

 about 5t p.m., and was astonished to see a very fine arc of light 

 completing the circle. I at once apjilied a power of 80 in a 3-in. 

 telescope, but the arc of light had vanished. In its place, however, 

 I now saw, quite distinctly, the whole ot the dork |)ortion of the 

 disc having a dull, greenish tint. This was, of coui-se, 6d. Oh. after 

 new moon. Looking without the telescope, I again quite dis- 

 tinctly saw the fine bright arc, but again the telescope dispelled 

 it. I now looked with a much higher power, with an ordinary 

 field-glass, and with a good binocular, but in every one the bright 

 arc had disappeared, though vnth the naked eye it still remained. I 

 repeated the experiment several times with the same restilt. 



