Polytechnic Association. 931 



Dr. Bradley — It may be added that the moist atmosphere not only 



absorbs the heat that is radiated, but radiates it back again to the 



earth. 



Adjourned. 



April 12, 1872 



Prof. S. D. Tillman, in the Chair; Robert Weir, Esq., Secretary. 



Balance Elevator. 

 Mr. Charles B. Sawyer, of Fitchburg, Mass., exhibited and 

 explained a model of his balance elevator. He claimed it to be a 

 balancer of speed, and that by its use the velocity of elevation could 

 be readily doubled. After some discussion on its merits, the Chair- 

 man introduced the newly elected president of the Institute, Dr. F. 

 A. P. Barnard, who spoke substantially as follows, on the subject of 



Metrological Reform. 



I have been requested to address you this evening upon the present 

 state of the question of metrological reform. When we speak of 

 the present state of anything, we imply that there is something in the 

 existing condition of the matter spoken of, which makes it differ from 

 the past. In order to understand the present state of this question of 

 metrological reform, it will be necessary to look back to, and compare 

 it with, the characteristics of its past state. "We will therefore go 

 back one century, to the year 1772, and see what progress has been 

 made, since that time, in regard to systems of weight and measure. 



The characteristics of that age were these two : 



1. A wide diversity of systems, different countries, provinces, dis- 

 tricts, and even towns, having been in this respect independent of all 

 the rest. 



2. Confusion in the systems themselves, not only in regard to the 

 manner in which the different weights and measures were derived 

 from their unit bases, but also in the fact that there existed a great 

 many different systems of weights and measures in the same country, 

 the same province, the same district, and even in the same town. 



But notwithstanding this wide diversity, it is nevertheless true that 

 the names of the weights and measures throughout all Europe, 

 throughout all Christian nations, were the same ; not that they were 

 the same words, but that the names in different languages had the 

 same significance. All the people in Europe had an ell, they all had 



