Gum arabic 2 ounces Gum tragacanth 1-1/2 " Isinglass 1-1/2 " Sugar 1/2 " Water 3 pints These ingredients should all be dissolved, and then boiled down to the proper consistency, by means of a gentle heat. I will give another composition, which will serve a good purpose, and keep for a long time:-- Water 8 ounces. One table spoonful of wheat flour Powdered alum 40 grains. Powdered resin " Brown sugar 1 ounce. Bichloride of mercury 20 grains. This last composition may be more convenient for operators, and it will answer the purpose well. It is thought by some to be the _best_ and _most durable_ paste yet prepared for the purpose. =FACTS WORTH MENTIONING.= [Sidenote: FACTS WORTH KNOWING.] _The Poisonous Effects_ of cyanide of potassium upon sores, may be obviated by immediately applying some of the positive developing solution, described at page 62. By this means much annoyance may be avoided to persons afflicted with chapped or sore hands. _Bending Glass Rods_ or tubes can be easily done by subjecting them to the blaze of a spirit lamp--the same as that used for gilding the daguerreotype. First hold the rod just above the blaze, then gradually allow it to descend into it, imparting to the rod a rotatory motion with the finger and thumb: this will soon cause a softening of the glass, when it may be bent to any desired shape. If the ends are to be bent to form hooks, another small piece of glass, or any warm metal, may be placed upon the end, in the blaze of the lamp, and as soon as thoroughly softened, it can be pressed or bent to form the hook. By filing around a glass tube or rod, it may be easily and safely broken at the desired point, by giving it a sudden jerk between both hands, holding it close to the encircled part. _Cementing Glass_ may be readily accomplished by placing the two ends together in the blaze of the lamp, and holding them there until they attain a sufficient degree of heat to slightly fuse: when cool, the ends will be found perfectly united.