Apeil 10, ISSj.] 



KNOWLEDGE • 



315 



0\iv inbrntoisj' (Column. 



We give here, \ceek ty ireet, a terse description of such of the many 

 »ni'en(ions as \ce think may be of use to our readers. Where it is 

 poss\ble, the number of the patent is quoted, to enable those tcho 

 desire fuller information to procure the specification from the 

 Patent Ofice in Cursitor-street, Chancery-lane. We shall, getie- 

 rally speaking], confine ourselves to (/'« more recent inventions; but 

 it often happens that an article comes under our notice ichich, 

 although not quite novel, is worthy of mention for its xitility and 

 ingenuih/. In such a case we should not hesitate to refer our 

 readers to it. And while tre thus increase the interest of our pages, 

 we at the same time assist the inventors by giving greater publicity 

 to their inventions (Kxowlkdge being a popular f7in<7«:ine) than 

 is accorded by the most excellent trade journals 



ADJUSTABLE INSTANTANEOUS SHUTTER. 



[Patent No. 77-«5. 18S4. j— The principle of this shutter, patented 

 by Mr. Thomas Furnell, consists in the nse of two Hiipa so adjusted 



F._- 1. 



Fig. 2. 



to each other, by mechanical means, that the amount of exposure 

 that can be given to the foreground, in proportion to the sky, can 



be governed at will ; as the bottom 

 flap c*n be set and clamped in any 

 desired position, the top flap remain- 

 ing closed ready for exposure. The 

 bottom flap has a sweep of about two 

 hundred degrees ; the top flap only 

 about ninety-five degrees, and re- 

 mains as a sky shade. Fig. 1 shows 



^ ■ the shutter set ready for action ; 



S ^^^^ ==""~4 ClQ Fig. 2, arrested at full open ; Fig. 3, 

 " ^^^^^^^^^^3 >>- folded for portability. The ratio of 



movements of the two flaps are so 

 *'=■ arranged, that the first slow move- 



ment of the bottom flap causes a first rapid movement of the top 

 flap, which slows as it rises. This gives a greater proportion of 

 exposure to foreground, and less to the sky ; and to counterbalance 

 this, the bottom flap commences slow and increases in speed as it 

 riaea, and so cuts oft the exposure of sky portion. The following 

 are the different positions taken by the flaps ; — 



/ 



Fig. 4. 



\ 



\ -J 



Fis 



Fig. G. 



Fig. 



If the bottom flap be set, as shown in Fig. 4 or instantaneous 

 work, the foreground receives the greatest amount of exposure, 

 although the motion is extremely rapid. If the bottom flap be set 

 as at Fig. 5, both flaps rise together until full open, then the top 

 one remains as a sky shade, and the bottom one flies up and closes. 

 If the bottom flap be set as at Fig. C, it is the most suitable for sea- 

 scapes, as the top flap arrives at the horizon line at the same time 

 as the bottom flap arrives at full open. This flap then flies up and 

 closes, so that the sky portion receives Vjut a very small amount of 

 exposure in proportion. Fig. 7 shows the position of the flaps at 

 the end of exposures. Arrangements are made for prolonging the 



time of exposure at full open, or for focussing when required. The 

 flaps are formed of ferrotype plate, and n\iulo to act as springs, to 

 resist jar, or shake. Tliis jilan pr^ives very effective, as the 

 movements cannot bo felt if luUl in the hand during action. This 

 is one of the points claimed in tlie patent. Tlio apparatus is very 

 ingeniously designed, and, with duo care, there is no reason to 

 anticipate its failure. It is claimed to be uneiiualled by any other 

 shutter extant for giving cloud-effects, with ecjual density of 

 negative throughout of foreground and sky. 



D1!.\IN INSPECTION PIPE. 



Mr. G. C. Davies, of G5, Lausanne-road, S.K., has patented a 

 "Cast-iron Inspection or Access I'ljio for Ilouse-drains," which has 

 every prospect of being very extensively adopted. 



There are several devices in stone or earthenware that have been 

 used for the purpose of inspection or access to house-di-ains, and 

 which may be all very well for rain or surface water, but from one 

 cause or other they are defective for the purpose of soil-drains. It 

 is asserted that an inspection-pipe to bo depended on for soil-drains 

 could not well be made in any earthenware material ; for if the cover 

 over the aperture is bedded down and made gas-tight at the time 

 (an operation that requires some care to ensure it being so) the 

 joint is always liable to be broken and the cover lifted by heavy 

 flushing, or by the drain getting stopped up, besides being always 

 liable to breakage by the workmen. 



These inspection pipes invented by Jlr. Davies are made of strong 

 iron castings, 2 ft. G in. long, and can be made to suit any size pipes, 

 either iron or stoneware. They are especially intended for the use 

 of soil or foul-water drains, in order to keep the foul-gas area of 

 same to the minimum, and to avoid the expense and nuisance of 

 breaking open the drain, should it at any time get choked or stopped 



The pipes are provided with a longitudinal aperture, which is 



ordinarily covered in, 



M 



//& - , 



E IB 



Fig. 1. 



but which, when neces- 

 sarv, may be removed 

 for inspection purposes. 

 Fig. 1 is a plan showirg 

 the under side of the 

 cover over the inspec- 

 tion aperture, A beiup 



the curved soflit forming a section of the inside periphery of the 

 pipe. B B shows the position of the gun-metal screws, for se- 

 curing the cover to the pipe. D is the groove for receiving 



the stuSiug material for making the gas-tight joint. Fig. 2 

 is a plan of the pipe with the cover off, showing the 

 aperture for access, Ac, E being the tongue nmning round 

 the aperture corresponding to the groove D in the cover. 

 Fig. 3 is a transverse section (enlarged scale) through the centre 



of pipe, A, showing the in- 

 side of the cover when fixed 

 in position on the pipe. B, 

 the gun-metal screws. C, 

 tho eyes at each end, when 

 necessary, for lifting the 

 cover. D, the groove-and- 

 tongue gas-tight joint, run- 

 ning round tho iugpection 

 aperture. The gas-tight joint 

 is made by filling the groove 

 D in the cover level all round 

 with the stuffing material ; 

 clearing off a'.l dirt and sur- 

 plus cement from the parts 

 forming the joint; placingthc 

 cover in position, pressing 

 close, and screwing down. 

 The cement or stuffing may 

 be white lead, with jusi 

 sufficient tallow when neces- 

 sary to keep it from hard- 

 ening. Id will be noticed 

 that no skilled labour is requisite to make this joint. Tho advan- 

 tages secured by using these pipes are : — 1. Simplicity in making 



Fig. 3. 



