126 Association of American Geologists and Naturalists. 



The time and opportunity for more extensive observation which were 

 denied to me, it was the peculiar good fortune of Mr. Dana to enjoy. 

 That they were improved to the utmost, no one acquainted with that 

 gentleman, much less I, whose happiness it was for so long a period to 

 be his friend and companion in many a toilsome excursion, can for a 

 moment doubt. The data to which I allude above as deficient, at least 

 a very large part of them, have been collected by his zealous research- 

 es, and practically applied to the determination of problems which I had 

 no means of solving. It is for him to decide then, upon the value of 

 the few suggestions thrown out by me as the result of my more limited 

 examinations ; and I doubt not that with a knowledge of the facts now 

 before him, I shall receive at his hands all which is justly due them. 



Entitled equally with myself to whatever credit may attach to an ori- 

 ginal discovery of the great influence of temperature or oceanic climate 

 on the distribution of corals, Mr. Dana has been enabled by a long con- 

 tinued and careful series of observations, to achieve the grand object of 

 ascertaining the entire range of temperature limiting their growth. 

 This is a discovery solely and exclusively his own, so far at least as I 

 am concerned, since all that I ever flattered myself with having deter- 

 mined on this point was the approximate range of their greatest devel- 

 opment. His is the rich harvest of facts, and their application in a 

 wide field of observation, — mine but the scanty and hurried gleanings 

 of a limited one, a feeble and comparatively trifling contribution to the 

 general stock of knowledge ; but in casting it in, I feel proudly con- 

 scious that it was honorably acquired, and that had my opportunities 

 continued, the results might not have been far inferior to those present- 

 ed by my more fortunate fellow laborer. 



Prof. W. R. Johnson presented a statement of experiments to 

 determine the evaporative power and other properties of coal from 

 different coal formations of the United States, and other countries. 



He exhibited drawings and sections of the apparatus with which his 

 researches had been conducted, gave a tabular list of the coals assayed, 

 mentioned the nature of the questions sought to be determined, the 

 cltisses of observations necessary to solve the several problems present- 

 ed for solution, and the results of many of the experiments in regard 

 both to the practical efficiency and the actual constitution of various 

 coals. In analyzing the gaseous products of combustion, the actual 

 composition of those materials gave an opportunity of determining the 

 amount of heat expended on the air used for combustion, the moisture 

 it contained, and the water eliminated from the coal itself, as well as 

 that employed to evaporate water from the steam boiler. By means of 

 the calculated results thus practically obtained, compared with the ulti- 



