May 10, 1883] 



NA TV RE 



33 





four spectroscopes fed by the light reflected by a siderostat 

 of 30 cent, diameter, these four spectroscopes being 

 bracketed together very much like a Gatling gun, and 

 pointed to the siderostat, which has a very excellent 

 clock attached to it. The first spectroscope, called the 

 " Hilger," in the programme, is an integrating one, and 

 will integrate for us the light of the whole region round 

 the sun during the entire period of totality on a plate 

 which is allowed to fall very slowly by means of a clock- 

 work arrangement. If any change, therefore, takes place 

 in the spectrum of these regions during this period, it will 

 be recorded on this moving plate in historical sequence, so 

 that, the beginning and end of exposure being known, 

 the time at which any definite change takes place can be 

 determined. The Rowland grating coming next on the 

 list, which was generously given to Mr. Norman Lockyer 

 by Professor Rowland, is one of ten feet focus, and has 

 a large surface with 14,000 lines to the inch, forming of 

 course a most excellent and simple prismatic camera, the 

 first and second order spectra both being utilised. The 

 prismatic camera and slit spectroscope of two prisms 

 were two instruments arranged by Capt. Abney for the 

 eclipse last year. They are on the model of the instru- 

 ments designed for the eclipse of 1875 > n Siam, but have 

 the advantage of possessing plates which are sensitive 

 to the whole of the spectrum. The work to be done 

 by the equatorial is of a very similar nature to that to 

 be attempted with the siderostat, except that it was 

 intended by varying the time of exposure from long 

 to very short periods to make certain of something. All 

 the cameras, except the " Hilger,'' in which the plate 

 moves by clockwork, are fitted with long plates, of which 

 only small strips are exposed at a time, and the exposure 

 is managed, not by changing the plate as in the ordinary 

 method, but by turning a screw. The word " expose " in the 

 table therefore shows the precise moment, at which, if the 

 instructions are carried out, a new strip of plat will be 

 exposed to the action of the light before, during, and 

 after totality, and it will be seen that the exposures 

 are varied both before and after totality, so as to get the 

 greatest possible difference in time during which each 

 part of the plate receives its impression. From a letter 

 received by Mr. Norman Lockyer from Messrs. Lawrance 

 and Woods, we know that the American astronomers in- 

 tended giving them all possible facilities for carrying out the 

 combined Royal Society and Solar Physics Committee's 

 programme ; and that the attention of the English 

 observers will be concentrated on the siderostat and equa- 

 torials, as two officers of the American ship have been told 

 off to work the photo-heliographs and look after the 

 eclipse clock, which is so arranged that it keeps all the 

 observers together by indicating to each one of them the 

 exact number of seconds still left for his work, with the addi- 

 tional advantage that each number of se:onds announced 

 by the officer in charge is a distinct order to do a certain 

 thing, as in the case of the various exposures indicated 

 in the list. 





LECTURES TO WORKING MEN 



'"THE three courses of Lectures to Working Men given 

 -*• at the Museum of Practical Geology, Jermyn Street, 

 during the present session, by the staff of the Normal 

 School of Science and the Royal School of Mines, came 

 to an end last Monday, and, as on former occasions, it gave 

 rise to regret that more cannot be done in this direction, 

 both with regard to the number of courses given, and the 

 number of persons accommodated in each case. The 

 theatre at Jermyn Street restricts the audience to something 

 over 600, while of late years the applications for tickets have 

 never been less than 2,000. The tickets for each course — 

 for which sixpence is charged as a registration fee — are 

 given only to bond fide working men, who must bring with 



them a paper on which is stated their name and occu- 

 pation. Some of the lectures of the last course — that 

 given by Mr. Norman Lockyer, on " The Earth and its 

 Movements" — were listened to by the Japanese Minister, 

 and an official connected with the Education Department 

 of Japan. At their request a list was drawn up showing 

 the trades of the audience. This list, in the case of 500 who 

 attended the last course, we are permitted to give, and we 

 think our readers will find it an interesting one. Seeing 

 that there is this anxiety on the part of working men to 

 learn, and that less than one in three of those so desirous of 

 learning can have an opportunity of doing so, we trust 

 that in future years the Lecture Theatre at South Kensing- 

 ton will be utilised in this direction, as well as that at 

 Jermyn Street. There is little doubt, of course, that a 

 Liberal Government, represented by the Treasury officials, 

 naturally anxious in all ways to protect the public purse 

 against all claims, whether good or bad, might object to 

 this being done at the public cost, but seeing that the 

 lectures are given as a labour of love by the various pro- 

 fessors such an objection would scarcely be urged, and 

 we confess too that we should not only like to see the 

 theatre at South Kensington utilised in this way, but the 

 theatres at University College, King's College, and other 

 institutions that might be named. We do not believe 

 that the professors at these institutions are less anxious 

 for the progress of knowledge among the working classes 

 than those who are connected with the Government 

 School, and this being so, we may hope to see at some 

 future time a united effort to supply what is at present a 

 great want, and a gap in our educational programme. 



Trades of 500 of the audience at the last course of 

 Lectures to Working Men, April and May, 1883 : — 



6 Iron Founders. 

 23 Instrument Makers. 

 37 Jewellers. 



1 Lamp Maker. 



1 Lead Glazier. 



3 Lithographers. 

 I Locksmith. 



4 Stonemasons. 



1 Mattress Maker. 



2 Milkmen. 

 6 Opticians. 

 9 Pianoforte Makers. 



3 Perfumers. 

 6 Photographers. 



1 Picture Frame Maker. 



16 Plumbers. 



2 Pocket Book Makers. 

 2 Polishers. 



10 Porters and Messengers. 

 6 Portmanteau Makers. 

 6 Plasterers. 

 1 Quarryman. 



6 Salesmen. 



5 Saddle & Harness Makers. 

 I Saw Maker. 

 I Soda Water Bott'.er. 



7 Shop Assistants. 



4 Stationers. 

 I Smith. 



1 Stoker. 



2 Storekeepers. 



17 Tailors. 



4 Teachers. 

 I Traveller. 



6 Tinmen. 



5 Turners. 



1 Twine Spinner. 



2 Umbrella Makers. 



6 Upholsterers. 



8 Watch Makers. 

 1 Warehouseman. 



3 Wheelwrights. 



7 Zinc Workers. 



1 Bag Maker. 

 6 Bakers. 



2 Basket Makers. 

 28 Boot and Shoe Makers. 



1 Brewer. 



2 Brush Makers. 

 I Billiard Table Maker. 



6 Builders (Foremen). 



1 Butler. 



3 Brass Finishers. 



2 Bricklayers. 



7 Bookbinders. 

 6 Cabinet Makers. 



52 Carpenters and Joiners. 



8 Coach Painters. 



9 Compositor-. 

 8 Carvers. 

 1 Ci^ar Maker. 



4 Chemists and Druggists 

 13 Clerks. 



3 Curriers. 



6 Dentists. 



4 Designers. 

 I Die Sinker. 



1 Draper. 



2 Draughtsmen. 

 25 Engineers. 



2 Engraver-. 



I Envelope Maker. 



1 Fishing Rod Maker. 



5 Ga-fitters. 

 I Gardener. 



7 Gilders. 



1 Greengrocer. 



2 Grainers. 



3 Glasscutters. 



4 Gun Makers. 

 7 Hatters. 

 I Hairdresser. 

 I Hinge Maker. 

 I Hammerman. 

 I Hemp Dresser. 



23 House Painters. 



