concerning Heat. 153 



at the beginning of this Memoir, we have only to repre- 

 sent these results by a figure in the following manner. 



On the horizontal line A E, Fig. 3, representing the 

 axis of the cylinder employed in the experiment, we will 

 take three points, B, C, and D ; one, C, in the middle 

 of the axis, being the situation of the central thermom- 

 eter, the other two, B and D, at the intermediate points 

 which the other two thermometers occupied between 

 the middle of the axis and its two extremities. 



Erecting the perpendiculars A/, B g y C /z, D /, and 

 E k, on the points A, B, C, D, and E ; and taking the 

 ordinate Af= 212, the temperature of boiling water, 

 B g = 162, the temperature indicated by the thermom- 

 eter B, C h = 132!, the temperature indicated by 

 the thermometer C, D / = io6-|, the temperature given 

 by the thermometer D, and lastly, E k = 32, the tem- 

 perature of water mixed with pounded ice, a curve, 

 P Q, passing through the points /, g, h, i, k, ought to 

 be the logarithmic; that is, supposing the temperature 

 of the surrounding air to be constantly at the tempera- 

 ture of melting ice during the experiment. 



But the experiment in question was made when the 

 temperature of the air was at 78 F. ; consequently, 

 reckoning from a certain point, taken in the length of 

 the cylinder, where the temperature was at 78, to the 

 extremity, E, the influence of the surrounding air, in- 

 stead of cooling the surface of the cylinder, heated it ; and 

 it is evident that the curve, P Q, must necessarily in this 

 case have a point of inflection. 



In fact, it appears on a simple inspection of the figure, 

 that the curve, P Q, has a point of inflection ; but we see, 

 likewise, that this curve is not regular. That branch 

 which is concave toward the axis of the cylinder is not 



