SCIENCE and INVENTIONS.

New Zealand Herald, Volume LVII, Issue 17380, 31 January 1920, Page 6 (Supplement)

SCIENCE and INVENTIONS.

G|p| :, A- MsoKimoAi, PILOT. •;. rj? r :C;V!-:. : ;:.V.;«I' the most 'ingenious of war in;.;f, ■ tentions is the "leader gear,'' . invented ■k-}C:>: by the British, for a certain war purss&\ pose. • 'rl ; a cable , laid ,'on ; ; the .bottom; of *■■!'.;-.•'- the sea- -say in the channelloading into j '_. ,a Jjirboor—is;traversed by: alternating ?£& :' '-..' current, 'it] is possible, by". means of deli'&■v .- cat devices installed on board : ship, for J ".: the navigator to see or hear indications J-'■'■'■ '■['■ of the presence cf such cable. So per?, . fect is tie. m»Aamsm that ■ a ship can proceed 'at 20 knotsi in fogs or darkness, feeling its way along the cable almost as '" precisely as a tramcar trolley follows the .-;; >. overhead wire. By leader ■: gear laid/ in sach areas as the .River St. Lawrence; . the entrance to tie Thames, or Halifax ■• ' ; Harbour, the Straits of Dover, etc.; in and out lanes of traffic can be maintained with ease in fogs. A PLASTER BOAT. . ; If we can have a : concrete.-boat', there ; TMemsno.iilerent reason why we cannot have one of plaster; and an inventor sin j ; Portland, Ore, has actually given us one. His boat is 15ft longhand.weighs 4001b. SSi:■ • .:■',;«it? ■■ sides : are three-quarters of iin ■" : .inch mm 1 thick, and s are made !of ordinary Build-! Mi tflrSi plaster. .;- The boat is cheaper than -a wooden one, and the - inventor believes ! . 'it will last longer. ■ Its advantage o*er ,' ' a concrete craft is mainly'that of light- - ness, " The construction is > also much J easier, since the plaster requires an, inner , '- and an cuter form to a much less extent i than the "concrete. In large pert this < lighter, material can. be laid down over a -, single form, much.-,like a series of coats «of paint. , a; The boat has bHa'pat in aim- <• mission, and seems to be quite seaworthy ~atid easily handled. ;'".' -."■:;;■>;■;'■*•'" " ■"•'■ .■ IV- -'. ■ " -.. ,- ■ ■■-- *. LIQEiraiKO LETTER ' SOETEE. . , *-?: The post office sorting mathin) is the latest ingenious invention adopted sby the "postal aadwrities in the UniUni States. . -> , Seated in front of a large pacht of let- ;'•'■■ t>. i rs, the j post, office, clerk ocl • has- to press a, button and the letters sStft themselves I - The operator works on a sort ;; :of keyboard, on each key ci which the ' name of a town is printed. Now, suppose .the'first letter is'*or Wellington." H \ l He presses the key with that name onit, and the letter is seized by a little pincer, (Separated,, lifted, and deposited in a little ■;;!&;> •compartment 2reserved for v ill the Wellington ■ letters: f ■ All? this : with 1 . lightning : rapidity, The operator's handiwork'as . quickly on - the yost office sorting machine as these of an experienced ,clerk' would - , i on a typewriter. .TJp to now these |3|sj machines We had only 90 keys; that is :to: say, t% can only 6ort-lett«O};f(Jr s 90 •towns ai,&'tim*. lie constructors ; are, however, F ~i>s»uft f to perfect » ; model containing SS& keys. ' They are also confi- . ,dent of feeag able in the near future to ._• ; -j.pply this method of sorting to parcels. k' W) SALYJSa VESSELS WITH LIMPETS. ',',,'■ .'>. In soma cases a vessel is so gelled on v , . the .bottom that divers \ cannot i«es ' be- ' neath it to attach the slings ; ana cables, ;t£i :p: and to.-inert this' difficulty a new method called the- "Limpet System" has ben ip;f A - ; ■;;.:.. devised ■■ by whiita .it be.»mes possible ;to ' - sUacb wire hawsto to the hull of a- sunken vessel The limpet is a soft iron body, ; carrying va ; nuinoer jof drill taps -- driven -by swafi motors, the current being supplied from : the salraga vessel. The ■ :;... limpet is lowered until it in' : contact with 1&} hull of the vessel, when it is • mugnotiued, causing it to cling .to• the plates. The> drills are then started, and after running a prodeiiermined lcngtii time tha cowent is switched off, the Em;f"X- pet is hauled to the surface, and the %_s■ c , drills, sore left tightly > fastened? to' the ' ship's hull The md?. of these drills m formed into eyes, to which the hawsers can bo attadiedi This method would be : available iff me either with, lifting gear on salvage vessels at the Barf* ; or with pontoons of the kind intended 1 .. :be srjjik,, attached,to^'-.Uie vessel, and the ■"-•.>. : oat—their buoyancy raising ti f. ■ ' -wreck suffiriantry for ft to b© towed inl j^;^shalloTr;water,-' when the- process is a posted. 'f - , -r. ■ " ' ' ' W&X-fi, ■ -.. • ■ -