Graniteware is proving desirable for making utensils for use on electric stoves, the conductivity of the glass coating being so low, that it conducts the heat to the top of the pan slowly so the food in it gets to cooking quicker than in utensils made of most of the other materials. Aluminum is easily dented and warped by extreme heat. It is attacked by some strong acids and strong solutions of salt, soda and fruit juices. Aluminum may be hardened by the addition of six to seven per cent of copper so that it can be cast into utensils. Great care must be used not to use cleaning powders which contain strong alkalis for cleaning aluminum ware. It has light weight, and, when polished, is very attractive. With proper handling, it gives good service. =197. Mixing Spoons.= The wooden mixing spoon gives best results, as it does not mar the utensils, and the handle does not become as hot as metal. Hard maple or orange wood cut in a plain design makes the best spoon. Acids do not attack it. Plated silver or solid nickel spoons come next in usefulness. Softer metals wear off too fast to be satisfactory. Nickel is a most desirable material for household utensils, but is very expensive. It is not in common use in this country. TABLE SHOWING CONDUCTIVITY AND SPECIFIC HEAT OF METALS ====================+====================+========================== METAL | CONDUCTIVITY | SPECIFIC HEAT --------------------+--------------------+-------------------------- Silver | 1.00 | 0.0559 Copper | .74 | .0923 Aluminum | .48 | .2022 Tin | .15 | .0509 Iron | .12 | .1098 Glass | .0017 | Silicon | | .159 at 10° C. | | .2029 at 232° C. Nickel | | .1084 Tungsten | | .035 --------------------+--------------------+-------------------------- CHAPTER XXVIII PARERS, SEEDERS, GRINDERS, SLICERS, ETC.