A reader recently asked for a formula for making hectograph pads, and through the courtesy of Mr. H.E. Smith, chemist and engineer of tests of the L. S. & M. M. S. K. R., we are enabled to fnrnish the following information :

Clear hide glue, 1 lb.

Water, l 1/2 pts.

Glycerine, 2 1/2 pts.

The glue should be of good quality, and the kind that comes in transparent, light brown sheets, as the white or brown opaque glue does not give as good results. Break the glue into small pieces and soak it in the water over night in a covered vessel. Then melt it in a water bath, and add the glycerine, which should previously be heated to the same temperature as the melted glue. Stir only as much as is necessary to mix the glue and the glycerine, as too much stirring introduces air bubbles, which are difficult to remove. Pour the hot mixture through a cheesecloth bag into the pans.

When the pans are filled and the jelly is still quite fluid, sweep off air bubbles or impurities from the sar-face with the edge of a card. Let the pans stand 48 hours before using. This formula calls for much less water than is usually required by other formulas since it is preferred to secure the requisite softness by means of the glycerine, which does not evaporate and allow the pads to dry out, as does the water.

In writing the original copy always use hard, glazed paper, and write with hectograph ink. In making the negative, moisten the surf ace of the pad with a cold, wet sponge, wiping off the excess of moisture. Dry off with a newspaper and let stand for two minutes. Place the original face down on the pad for from one to three minutes, rubbing down to a perfect contact, and then carefully remove.

In printing apply a clean sheet of any kind of paper so that it touches the hectograph at all points, rubbing as little as possible. Never use hot water for removing the negative; as soon as the copies are all made, wash off with a sponge and cold water and dry well with a newspaper. Never let the pad stand with ink in it after the copies are made, and always keep it closed when not in use.-"Am. and Eng. R. R. Journal. "