602 



Popular Science Monthly 



Drying Negatives by Heat from a 

 Kerosene Lamp 



THE invention illustrated is a simple 

 lamp heater for (juickly drying 

 photographic plates. In the old form of 

 lamp heater, the hot air from the lamp 

 is made to circulate in a chamber con- 



The hot air passing 

 over the plates is 

 not exposed to gases 



taining the [)lates, l)ut this exposes the 

 plates to the gases formed by the com- 

 bustion of the lamp and also to smoke, 

 especially if, as often happens, the lamp 

 does not burn well. In the new makeup, 

 care is taken that the plates are exposed 

 only to fresh air. As will be seen, the 

 lamp is placed in the sheet-iron box, but 

 it occui)ies a separate chamber. The 

 lamp chimney projects up into a tube 

 portion, and is prevented from over- 

 heating the metal by the use of an 

 asbestos packing. The photographic 

 plates are placed in two inclined cham- 

 bers which open into the lamp chamber. 

 The action of the lamp causes a suction 

 in the ui)per tul)e clue to the rising 

 current (jf liot air, and this causes air to 

 be tirawn into the front opening A. The 

 air passes up through the two plate 

 chambers and out through the ciiinmey. 

 Only fresh air circulates in the iilate 

 chambers. Plates are first put in metal 

 frames and these are slid into racks 

 inside the chamber through the end 

 door. If desired, .i ruby glass Iront 

 can be used at C so as to make the 

 devi(X' useful as a dark-room 1. intern. 



Making a Scrap- Book Out of Old 

 Ledger Covers 



A SCRAP- BOOK can be made at 

 home from an old ledger back, 

 pa]5er, twine, and glue, as follows: Take 

 an old ledger and remove from it all 

 pages, saving only the back. Next take 

 about one hundred sheets of heavy type- 

 writer paper (the number depends on 

 the thickness of the ledger) and cut these 

 to a size a little smaller than the back of 

 the ledger. Between each of the pages 

 place a thin strip of cardboard abf)ut 

 ^2 in. wide. Now take some sharp in- 

 strument, such as a large darning 

 needle, and punch holes through the 

 edge of the sheets of paper that contain 

 the thin strips of cardboard. Place these 

 holes about 2 in. apart. After they 

 have been made, thread the needle with 

 twine and sew them looseh' together by 

 passing the needle and thread in and out 

 of the holes you ha\c punched. 



When the sheets are fastened together 

 take a piece of linen cloth as long as the 

 sheets of paper and about 4 in. in width. 

 Where they have been fastened together 

 wet the edge with glue and press it in the 

 center of the cloth. After it has dried 

 put the sheets in the ledger cover and 

 fasten it there by^ gluing the cloth that 

 extends out on each side of the sheets 

 to the inside of the ledger cover. When 

 it is thoroughly dried you have a scrap 

 book that has cost you little or nothing. 



A Thumb-Tack Gage for a 

 Paper- Cutting Board 



THIC drawing shows an accurate and 

 easily apjilied method of gaging 

 a cutting-board to trim exactly to size 

 anv number of sheets. It consists of a 



The thumb-tnck can be set at any desired 

 point on the cutting-board for a gage 



tiuunii-tack stuck into the cutting-board 

 surface at the riglit spot to hold the edge 

 of the i)ai)er in i)lace. — C. P. I.KllMANN. 



