Page:Popular Science Monthly Volume 88.djvu/948

 920

��Popular Science Monthly

��A Hose Connection Guaranteed Water-Tight

THE hose connection illustrated, has an upper part with a tapered end to fit the rubber washer in the large end of the lower part. Near the end of each part, which engages the hose, is an enlargement to keep the hose from

\^^. /Rubber i\''as/?er

��r

��-<^--

��—li-

��z'

���Diagram giving proper dimensions of hose connection

slipping off. Small clamps can also be used. Each flange consists of 2 segments of a circle, 90°, each opposite the other and tapered, or rather increasing in thickness, so that after the 2 parts are placed together, a 90° turn, and some- times less, will make the connection perfectly tight. — Joseph K. Long.

���— •■ r -K-t -,+ -1+ - L-T ,]

����H^

��A ninety-degree turn makes this connec- tion perfectly tight

Silver-Plating Glass

HERE is a good recipe for silvering mirrors or silver-plating glass of any kind.

Two solutions are used. For con- venience they may be designated as solu- tion No. I, and solution No. 2.

Solution No. i is prepared as follows: To a one per cent solution of silver nitrate add pure aqua ammonia, drop by drop, till the precipitate is almost all dissolved. Let this stand and then filter. The filtrate is solution No. i.

To prepare solution No. 2 : Dissolve one gram (.04 oz.) of silver nitrate in a little water and add to 500 cubic centimeters (17 fluid ozs.) of boiling water. Then dissolve 0.85 gram (13.12 grains) of Rochelle salts in a little water and add to the 500 cubic centimeters of

��boiling water containing the silver nitrate. Boil for 20 or 30 minutes till the gray precipitate has collected, and filter the solution. This filtrate is solution No. 2.

The glass surface to be coated must be carefully cleaned with alcohol to remove all traces of grease and dirt. All other surfaces which are not to be coated, should be painted with melted paraffin after the glass has been cleaned with alcohol. This leaves a clean exposed surface on one side of the glass to which the silver will stick. In coating with the paraffin, be careful not to get any on the clean surface. Mix equal parts of solutions No. i and No. 2, and place the glass to be coated in the solu- tion. The silver will stick better if the clean exposed surface of the glass is rubbed with a small cotton swab, saturated with the solution. Leave the glass in the solution till the coating of silver is as heavy as desired. Then scrape off the paraffin, being careful not to mar the silver deposit on the rest of the glass. If desired, to protect the silver coating, two thin coats of white shellac may be applied. — L. G. Haskell.

How to Mend a Broken Casting

WHILE placing a casting in his lathe, ten years ago, a machinist permitted it to drop on the tailstock, breaking the casting, as shown in the illustration. It was a serious break in those days, when cast-iron could not be welded so readily as now. The only recourse was a harness of two turned rings and two bolts. The arrangement may be seen in the illustration; it does not look good, but it is still doing service. — N. G. Near.

���This mended casting has done service for ten years

�� �