314 



On the Rapid Production of Steam. 



EIGHTH SEKIES, 



With an ingot of pure gold, weighing 14 lbs. 8^ oz. avoirdupois,* 

 and other circumstances as in preceding series, the following re- 

 sults were given. 



Heat of metal. 



Red in the dark. 



Comparable. 

 Comparable. 



Observations. 



' The water had remained expo- 

 sed a short time, and probably 

 lost a few deg's before this exp. 

 Plunged by degrees. 

 Do. 



The mean, of the two experiments, made at the temperature of 

 comparison, is 4:2j%% pounds of metal to each pound of steam. The 

 extremely low specific heat of gold, renders necessary- every precau- 

 tion formerly detailed, in regard to avoiding loss of temperature in 

 the water between two successive experiments, and also demands 

 peculiar accuracy and dispatch in the process of weighing. After 

 all, the efforts, which were made to insure a correct result, it may 

 have happened that a few degrees of heat, in the gold, were expen- 

 ded in raising temperature, and a corresponding deficiency in the 

 quantity of heat of elasticity may have been the consequence. 



The following summary exhibits a comparative view of the several 

 metals submitted to trial, as shown in the preceding series, indicating 

 the mean result of those experiments in each series which were 

 made at the comparable temperature. . 



From all the preceding series it appears that at comparable tem- 

 perature, each pound of steam requires for its production of 



Cast iron. 

 Wrought iron. 

 Wrought copper. 

 Cast Brass, 

 Standard silver. 

 Pure gold, 



8^ 

 9 



10-3-5- 



10-9-6- 



18-8-3- 

 ^'^ I 



^■^ 1 



pounds 



^ The above mentioned mass of gold, at the mint valuation of 42 j cents per grain, 

 was worth ^4105.448. For the use of this, as well as of several ingots of silver, and 

 for other conveniences in these experiments on the precious metals, I am indebted 

 to the politeness of Dr. Moore, superintendent—Mr-. Eckfeldt, chief coiner— and 

 other officers of the United States' Mint. 



