102 



KNOWLEDGE & SCIENTIFIC NEWS. 



[May, 1904. 



33.733- Photography. 



Oct. 30. 



Beck, C, 68, Cornhill, London 



Ciimciiis : rallir slidt's : sJiullcis. — Relates to a camera with roller 

 slide and two shutters, one at the focal plane and one at the lense. 

 The camera is shown in Fig. i, with the bellows removed The 

 rollers 12, 11 of the bUnd shutter are mounted between rollers i of 

 the roller slide. The front 3 is mounted on metal runners 5 fixed in 

 the middle of the hinged base-board 7. To fold up the camera, the 

 front 3 is pushed back, the stays 6 are disconnected, and the base- 

 board 7 is folded up on the back. The camera is supported by a 

 metal frame 8, which is pivoted to a base-board 7 so that it can be 

 turned over the end of the latter in folding up the camera. The 

 focussing is done by moving an arrow on the front along a scale of 

 distances on the base-board, lines being marked on each side of the 

 arrow to indicate depths of focus for tlie different lense apertures. 

 The lense shutter, which consists of two hinged plates 15. is closed 

 while the roller bhnd shutter is being set by turning the button 25. 

 To make an e.xposure, the button lO is depressed, a movement 

 which, acting through the links 17, 18, 20, or through a ffe.xible 

 shaft, opens the shutter 15, then lifts the pawl 14, which releases the 

 roller blind shutter, and makes an e.xposure. The blind shutter has 

 two apertures, one equal in size to the aperture 2 in the back of the 

 camera, and a narrower aperture for more rapid exposures. There 

 is an adjustable stop arrangement in the blind roller 12 liy means of 

 which either of these apertures can be used This stop arrange- 

 ment consists of an axial screw actuated by the roller 12 and thus 

 moved lengthwise, till it comes against a stop and arrests the 

 shutter. For a time exposure, the large aperture of the roller blind 

 is brought opposite the opening 2 and held there by the pawl 14, 

 which is locked by a sliding plate 81 The time e.xposure is then 

 made by the front lense. A method of holding the spools of roller 

 slides so that they can be easily removed or inserted is described 

 A spring is placed at one end of the spool so that it can be pushed 

 back to liberate the other end. 



23,858. Therino=electric batteries. Johnson, J Y , 47, 

 Lincoln's Inn hields. London — (ir,i//'i~ Co., A.: Bli-ii-lnlnissf, 

 Fianhfi'it-on-tke-Muiii. Ccimnny). Oct. 31. 



FIG. I 



Consists in the employment of special 

 shaped bars for use in a thermo-electric 

 battery. The bar 6, consisting of a 

 nickel-copper alloy, is bent as shown and 

 has a barr cast on one end, this bar being 

 an antimony-zinc alloy to which iron or 

 cobalt has been added, in order to raise 

 its melting point and to increase its 

 mechanical strength. A copper strip;/ is 

 attached to the nickel at its cold end, to 

 act both as a support for, and to facilitate 

 the cooling of. the nickel, whilst a copper 

 plate is attached to the antimony for the 

 same purpose. The short horizontal and 

 vertical arms of nickel, which are heated 

 to produce the thermo-electric current, 

 may be replaced by silver, or an alloy of 

 copper and silver, or copper coated with 

 silver or gold ; or the short horizontal 

 arm alone may be so replaced. 



12, Kaiserstrasse, Nurem- 



9, 749. Photography. Beck, F 



berg, Germany. Sept. 9. 

 Ciimeni s^i;«?s.— Relates to a supporting-device for hand cameras, 

 which is detachable from the 

 camera. It consists of a base- 

 board in two parts ii; b hinged at c. 

 At the back of the part j is pivoted 

 a bracket d having a sliding bar e 

 with an arm /, which is pressed 

 down on the camera back g and 

 7 Jll LU '- ^i' ! ! J ' L clamped by the lever /;. The 



'i i, ^ nXlXP'^^J front / of the camera is held by a 



spring clip which is pivoted to the 

 front of the part h. When the sup- 

 port is not in use, the brackets d. i 

 are folded down flat, and the parts 

 I', b are folded together on the 

 hinge r. The camera may be laid 

 on its side on the support, when the front I rests on the block m, 

 and the arm / is pushed further down. 



23,969. Arc light projectors. 



Engelsmann, a., II, Armin- 

 strasse, Stuttgart, Wiirtem- 

 berg, Germany. Nov. 3. 

 Rijii-cters for projecting light 

 from alternating-current arc 

 lamps The light from the car- 

 bons />, I" is reflected by two 

 annular parabolic mirrors d, f, 

 that falling on the mirror /being 

 reflected again by an annular mir- 

 ror 4', within the mirror <l. 



N-Rays 



Stored up by 

 Bodies. 



Certain 



III the course of hi.s investigations of the N-rays, Professor 

 Blondlot, as pointed out in a note just read before the French 

 Academy of Sciences, happened to state an interesting phe- 

 nomenon. N-rays being produced by an Auer burner enclosed 

 in a lantern, would traverse first one of the walls formed by an 

 aluminium foil, to be concentrated afterwards by a quartz 

 lease on phosphorescent calcium sulphide. The Auer burner 

 ha\ing been extinguished and taken away, the phosphorescence 

 would persist with nearly all its brilliancy, and on interposing 

 a lead screen or moistened paper or else the hand between the 

 lantern and the sulphide, the latter would be darkened ; 

 nothing was thus changed by the Auer burner being taken 

 away but for a gradual decrease in the strength of the effect 

 observed. Twenty minutes afterwards, they would still per- 

 sist though being nearly insensible. 



On closer investigating, the conditions of this surprising 

 phenomenon, Blondlot soon noticed that the quartz lense had 

 itself become a source of N-rays; as, in fact, this lense was 

 taken away any action on the sulphide would disappear, 

 whereas by approaching the lense, the sulphide was made to 

 take a higher brilliancy. The author then exposed a quartz 

 plate 15 mm. in thickness, the surface of which was a square 

 of 5 sq. cm. to tlie action of N-rays given oft" from an Auer 

 burner through two aluminium foils and black paper, when the 

 plate would become active like the lense ; as, in fact, the sul- 

 phide was approached, a phenomenon would be observed as 

 if a darkening veil were taken away from it. In all these 

 experiments the secondary emission from the quartz adds its 

 effect to the N-rays directly emanating from the source. This 

 secondary emission resides throughout the mass of the quartz, 

 and not only on its surface, as by placing successively several 

 quartz plates one on another, the effect is found to augment 

 with each added plate. Islandspar, fluorspar, glass, &c., 

 show a similar behaviour. A Nernst lamp filament will remain 

 active for several hours after the lamp has been extinguished. 

 A gold piece, on being laterally approached to the sulphide, 

 subinitted to the action of N-rays, would take a higher bril- 

 liancy ; lead, platinum, silver, zinc, &.C., would produce the 



