August 22, 1895] 



NA rURE 



401 



The films are supplied ready packed and arranged in the 

 nrder in which they are to be inserted into the magazine. 



To understand more clearly the position of the notches, it is 

 liest to take the empty magazine in hand, and entirely withdraw 

 the black exposing shutter. It will then be seen that the front of 

 the magazine is provided along its sides with two series of pro- 

 jecting tcelh ; it is upon these teeth that the films inserted into 

 the holder are supported. At one ^wX of the magazine, which 

 we shall call the top, is a button ; if this Inuton be pushed from 

 one side to the other, this movement will shift all the sorting 

 teeth at the same time, so that they will occupy positions a little 

 to one side of their former ones. 



A film introduced into the magazine will then be supported by 

 the sorting teeth, when these stand in the original ]>ositions ; if 

 this film be put into the holder with its notched corners 

 towards the top end of the magazine. It will, however, fall 

 past the sorting teeth, which pass through its notches, when the 

 change button is moved to one si<le and the sorting teeth stand 

 in the second position mentiimed. 



The process of filling the magazine is very simple, for the 

 pressure-board has only to be removed, and the films inserted 

 into the holder with the white film downwards, i.e. towards the 



an apparatus room, and workshop. At the back is another large 

 r<jom to be used for a natural history museum. 



Every room is fitted with electric light and Ridge ventilation, 

 which keeps the air pure even when filled with workers. The 

 lecture theatre, which is capable of hohling from 80 to lOO boys, 

 is fitted with a solid slate table on brick piers, so that work can 

 be done on it with the most delicate instruments without inter- 

 ference from the vibration of the floors. The fact that the 

 rooms are all on the ground floor, gives the opportunity of 

 ])utting all delicate instruments, such as balances, galvanometers, 

 &c. , on brick pillars, and thus to get rid of any vibration 

 whatsoever. 



The main laboratory contains ten tables for elementary physical 

 measurements, two for calorimetry, two for magnetism, and two 

 for heat experiments. Each table has a cupboard containing 

 the necessary apparatus, and an electric lamp giving direct 

 illumination on the tables without shadow or glare in the eyes of 

 the w'orker. 



Of the two smaller laboratories, one is an optical room, which 

 can, of course, be completely darkened, and is fitted with two 

 optical tables and a heliostat, so as to use direct sunlight as often 

 as possible. 



pointers, and eventually towards the lens. .Should there remain 

 m the magazine any unexposed films, with their backings, 

 and it is merely required to a<ld to their number, the additional 

 films with their backings may be dropped into the holder by 

 twos or threes, due care being taken that the alternate arrange- 

 ment be maintained. 



The wholo process, although somew hat lengthy to describe. 

 !s in itself very simple and neat, and can be at once grasped by 

 an examin.atitm of the holder itself in daylight. 



THE NEW 



NATURAL SCIENCE 

 AT RUGnV. 



.SCHOOLS 



T 



HIS new building for the physical part of natural science, 

 which has recently been opened at Rugby School, is well 

 worth a visit from any one engaged in teaching that subject. 

 The building, owing to want of funds, is not at present of a per- 

 manent nature, being of the felt and matchbnarding ty])c, and in 

 consequence has no pretensions to structural beauty ; but when 

 fiinds are forthcoming, no doubt the whole will be built in brick, 

 and this will enable any alteration or improvement which may 

 then be deemed necessary to be made. The building com- 

 prises a lecture rotmi, a large laboratory, two small laboratories, 



NO. 1347, VOL. 52] 



The other is the electricity room, containing two tables for 

 frictional, and two for voltaic electricity, with cupboards, &c., 

 as in the main laboratory. 



I'rovision has been made for a small engine and dynamo for 

 electrical work, and these will no doubt be added in time. 



The whole is under the charge of Mr. L. Gumming, to whom 

 the arrangeivient is due, and who is certainly to be congratulated 

 on the result. 



Every boy who takes up natural science at Rugby not only goes 

 through a course of lectures, but has also to do ex]ierimental work 

 himself in the laboratciry. This enables hiiti to grasp the subject 

 much more thoroughly, and to remember it much better than if 

 he attended the .-Wctures only. That this method has had 

 excellent results, will be seen by the number of successes in 

 natural science that Rvigby has gained of late years in scholar- 

 shi[) and other examinations. 



EVIDENCE OF A TWILIGHT ARC UPON 



THE PLANET MARS. 

 ■p^URINt; last summer and autumn Mr. Douglass made at this 

 '-^ observatory 341 micrometric measures of the diameters of 

 Mars. In addition to their general value as micrometric 

 measurements, these turn out to be of a peculiarly interesting 



