_So as to be held in the hand._ _To actual temperature._ Min. Min. Lead in 10-1/2 In 42 Gres in 12-1/2 In 46 Common marble 13-1/2 In 50 Copper 19-1/2 In 51 Iron 23-1/2 In 54 By a third experiment, with a less degree of fire than the preceding, the same bullets with a fresh tin bullet, cooled in the following manner. _So as to be held in the hand._ _To actual temperature._ Min. Min. Tin in 7-1/2 In 25 Lead in 9-1/2 In 25 Gres in 10-1/2 In 37 Common marble 12 In 39 Copper 14 In 44 Iron 17 In 50 From these experiments, which I made with as much precision as possible, we may conclude, first, that the time of refrigeration of iron, so as to be held in the hand, is to that of copper : : 53-1/2 : 45, and so to the point of temperature : : 142 : 125. 2dly, That the time of refrigeration of iron, so as to be held in the hand, is to that of the first refrigeration of common marble : : 53-1/2 : 35-1/2 and their entire refrigeration : : 142 : 110. 3dly, that the time of refrigeration of iron, to that of gres, so as to be held in the hand, is : : 53-1/2 : 32 and : : 142 : 102-1/2, for their entire refrigeration. 4thly, That the time of refrigeration of iron to that of lead, so as to be held in the hand, is : : 53-1/2 : 27 and 142 : 94-1/2 for their entire refrigeration. In an oven hot enough to melt tin, although all the coals and cinders were drawn out, I placed, on a piece of iron wire, five bullets, distant from one another about nine lines, after which the oven was shut, and having drawn them out, in about 18 minutes they cooled, _So as to be held in the hand._ _To actual temperature._ Min. Min. Melted tin in 8 In 24 Silver in 14 In 40 Gold in 15 In 46 Copper in 16-1/2 In 50 Iron in 18 In 56 In the same oven, but with a slower heat, the same bullets with an other bullet of tin, cooled, _So as to be held in the hand._ _To actual temperature._ Min. Min. Tin in 7 In 20 Silver in 11 In 56 Gold in 12-1/2 In 40 Copper in 14 In 43 Iron in 16-1/2 In 47 In the same oven, but with a still less degree of heat, the same bullets cooled,