364 



• KNOWLEDGE 



[Fsa 24, 1882. 



©urrifd. 



[267] — NKnixr. — An- iiclmlm external to our clustor? If po, 

 whiit n'lUioiiH lire ^fivori for believiii(f tlieiii to bo ? — A Dkrhy StI'dkxt. 

 [Nebulie nn< |iriivi'il, I think, by the renHoniiiff of Herbert Speneer 

 anil ntherH, tu lH>hing to our own 8tellnr syHtcin. I believe not n 

 tmco of nujfht externni to our cluster him ever been Hcen with th(> 

 teleiR'ope. Hut llio renxoniuK in not readily (f'^'i'" '" " sentonce. 

 In my " Tniverid'of Stars," it occupies two or three hundred pajjes, 

 nnd reriuiresa number of illustrated maps. — En.] 



[258] — Dnvixf! Wii.i) Fi.o«eb.s. — lam about to visit Ejrypt niid 

 Palestine, nnd wiHli to brinjf back some Hpeoimens of wild flowers. 

 Will you kindly inform nie how to dry them, so that they may 

 retain their natunil colour nnd form ? — 11. U. S. 



[259]— Ventiui.oquism.— Could nny render of KxowLEiMiK kindly 

 cxplnin to mo how ventriloquism is pro<iuced ?• — Erin. 



[2(30]— LioHTMXO. — There are two hills with an altitude of about 

 350 yards, and whoso summits are about 3,000 yards apart. On the 

 inner slope of one hill, and about half-way down, three cottajres 

 were built, nnd each of them was destroyed by lightning, separately, 

 and in a period of seven years. An opinion of what is the cause of 

 tho lightnin)^ concentrating itself and making this particular spot 

 its point of contact in preference to points of higher elevation will 

 greatly oblige. — Secret.\bv. 



[261] — Commercial Tables. — As the Education Code does not 

 require illegal or reputed " measures and weights " to be taught in 

 public elementary schools, can you inform me if commercial tables 

 (on cards or otherwise) of such as are only legal, or at any rate 

 practically used in trade, are published, or what is taught in the 

 London School Board Schools ?— W. F. 



[262] — Old Atlas. — Is the following work rare or valuable ? 

 " Atlas No\Tis sive Tabula; Geographicae totius orbis facicm partes 

 Imperia Regna ot Provincias exhibentes cxactissima cura iuxta 

 recentissimas obser^'atignos a^ri incisa- et venum expositcc h. Mattha>o 

 Seutter sac: Ca>s : Majest : Geogr : Augusta- Vindelicorum." It 

 contains some sixty maps, fifty by Seutter, and about ten by Lotter, 

 which are splendidly printed and coloured, and is of very large size. 

 — S. P. Q. E. 



[263]— Vegetable Food.— Will Mrs. Dr. Kingford kindly inform 

 the writer where he will find guiding information to enable him 

 with safety to enter on a course of vegetarianism ? Ho should like 

 for himself to test the truth of her statements. — Provost P. 



[261-]— Strata.— In travelling from London to Exeter (G.W.R.), 

 what formations are pa.s.5ed through •• I noted the following rocks 

 on the way down, but do not know to what age, &c., they belong ;— 

 London to Heading, gravel ; chalk nearly as far as Goring ; then, 

 through miles of grey clay to Didcot ; then red clay, light-yellow and 

 grey rock, to Corsham ; layers of rock and red earth outside Bristol ; 

 limestone beyond Weston Junction ; red soil opposite the Wellington 

 monument ; and slate at Exeter. Any information will greatly 

 oblige — Carus. 



[265] — Pigments. — Wanted a list of colours soluble in alcohol or 

 wood naphtha; especially what blues and blacks are soluble; 

 or name of books giving this information. — Arthl-b. 



[266]— SULPHI-B Cast.— I should be obliged by information how 

 a sulphur cast (which seems to give more perfect details than one 

 in any other substance) can be made a sufficiently good conductor 

 to electrotyi)e upon. I have tried rubbing it over with plumbago, 

 but it would not take the deposit of copper. — C. J. W. 



[267]— Thoracic I.nteckity. — I have been taught to regard the 

 chest as an air-tight cavity, any opening into which would cause 

 speedy death. In " Science for All," vol. ii., p. 305, it is related 

 that, through an opening in the chest, the heart has been handled. 

 Have 1 been misled, or has some unauthenticated statement found 

 its way into tho publication named f — C. M. 



[268]— PnoTocRAPHV. — Car. any person, through the medium of 

 these columns, give me informntion concerning photography ? 

 1 , where to get the cheapest articles required for photography ?' 2, 

 how to go about it ? and 3, whnt nre the chemicnis required ? — 

 Anon. 



TnE Magic Wheel. — If those of your renders who posses.s an 

 induction coil nnd n small vacuum tube will revolve their magic 

 wheel by tho light of their " tube," they will find it has the same 

 effect as the looking-glass, if a certain speed is maintained. The 

 revolutions, of course, should = number of breaks at contact 

 breaker -^ slits in disc— G. E. V. 



lUplifS to ©urn'fs. 



[195] — QflCK.siLVEB. — Your little note at the end of reply to 

 query 105, p. 321, regjiecting a dose of small shot, reminds me of 

 a custom here in Lincolnshire, which still provails amongat the 

 labouring class, of taking a few " shot corns " to cure ** the rising 

 of the lights." What this means I have never been able satis- 

 factorily to rliscover. I once know a well-to-do tradesman who 

 frequently took a dose. — C. J. C. 



[210] —The Iliad. — Newman's " Iliad " is much better than dry 

 Bohn's. — .Jaciebat. 



[228] — MiCBopnoNE. — Dry pile not at all suitable. The most 

 simple galvanic pair far better ; or a strip of carbon 1 in. x 3 in., 

 and zinc tho same size, separated by a pad of blotting-paper mois- 

 tened with weak sulphuric acid would be strong enough, and would 

 work ns long as moist. — G. E. F. 



[229] — Haib. — I do not believe there is a single authenticated 

 instance of " a person's hair turning white instantaneously from fear, 

 or other causes." On the other hand, it is well known that a 

 person's hair has become white in a short time, such as a single 

 night. Some years ago it was often stated, and as often contra- 

 dicted, that the hair of one of our most eminent statesmen was 

 the subject of this remarkable change. This case I can set 

 at rest, for the gentleman to whom I refer told a friend of 

 mine in this city (Manchester) that, when on a visit in Ireland, 

 he went to bed one night with dark hair, and rose next 

 morning with it exceptionally white. It is generally under- 

 stood that this only takes place when the person is soScring 

 from extreme mental an.xiety, intense grief, or bodily suffering ; but 

 these causes were excluded from the case of the statesman to whom 

 I refer. The medical man whom he consulted told him there was 

 no cause for alarm, and he thought no more of the matter. A 

 short time ago I heard him address an audience in this city, and I 

 am of opinion that his hair has become a shade or two darker, and 

 less snow-like in colour. I am not aware that the sudden change of 

 colour in human hair has been scientifically explained. — Wm. 

 Hobsfall. 



[229] — Hair. — The sudden change of the hair from dark to grey 

 which sometimes happens has never been satisfactorily explained. 

 It appears in some instances to be due to the development of air 

 between and among the cells composing the air. — Quain's" Anatomy," 

 vol. ii., page 226., Eighth edition. It is a fair explanation to say 

 that the change is probably due to an impression upon the nerves of 

 the scalp, in common with the rest of the skin, causing a contrac- 

 tion of the capillary blood-vessels, and a consequent with-holding of 

 pigment. — Robert M-vcphebson. 



[230] — Telescope. — The paint used for the insideof the telescope 

 was common, dry, black paint, mixed wth water, a quantity of thin 

 flour-paste being added by way of size. Diaphragms are placed in 

 the eve-piece tube ; there are none, however, in the principal tube. 

 —A. "p. M. 



[231] — Chemical Problem. — Let the required equation be 



aCu + bHXOj = xCu(N03) + yjH»0 + zNO. 



Then the multiples of Ca on the two sides must be equal ; » 



b 

 a=x; so b=2y; b = 2i-Hz = 2a-f z ; and 3b = 6x + v-(-2 = 6a+ 5- + s 



b 3b 



- "5" -H b — 2a = 4a -H — : 



whence b=- 



Sa la 2a. 



— T. J. P. 



[232] — Chemist. — " W. A. Fyson " shoald apply to the Registrar 

 of the Pharmaceutical Society, 17, Bloomsbury-square, W.C, for a 

 copy of " Regulations of the Board of E.xaminer3 " and " Uints to 

 Students. Both would bo sent on application with stamped 

 envelope. The fees are: — Preliminary (as apprentice), .i'2. 2s.; 

 minor (chemist and druggist), £3. 3s. ; major (pharmaceutical 

 chemist), .^5. 5s. The two former are compulsory-, the latter 

 optional. Certificates of having spent three years with a duly 

 qualified pharmacist, and of attaining the full age of twenty-one 

 years, are demanded before the candidate c,nn enter for the minor. 

 There is at present no compulsory curriculum at a school of 

 pharmacy, although such is the usual course, and costs from £15 to 

 £150. A few. however, with " severe study," pass without such aid. 

 The premiums for apprenticeship vary from nil. in hea\-y country 

 businesses, to £200 in first-class town pharmacies ; .£100 being near 

 the average in fair dispensing establishments. Before commencing 

 pharmaceutical studies, the preliminary or classical examination 

 must be psissed. After this the spare time of two years may be 

 well spent in studying with " Attfield's Manual of Chemistry'" 



