6 Transactions Texas Academy of Science. 
field of the astronomer been widened; the telescope has opened np fields 
for observation, the limits of which have been extended as the power and 
definition of the instrument have increased and accurately graduated cir- 
cles enable the astronomer to locate with precision the positions of celes- 
tial bodies at the times when pointings are made. Successive groups of 
bodies have thus been located and described and in later years photog- 
raphy has been able to automatically map the positions of bodies that are 
invisible under even the highest power of the best of modern telescopes. 
By the aid of the spectroscope man has been able to measure the proper 
motion of the stars, to tell us what chemical constituents enter into their 
composition, and something of their physical conditions. Astronomy as 
a pure science thus owes its progress largely to applied science, which has 
contributed the instruments employed and has installed them properly 
upon rigid supports or has transported them from point to point as 
needed. 
Experimental research has been the most potent factor in the advance- 
ment of physical science, many of the most important laws having been 
suggested by observed phenomena and others verified in this way. The 
applications of physical principles underlie almost all the operations of 
life more or less directly. At least a partial verification of some of the 
most important of physical laws, such as the laws of gravitation and the 
principle of the conservation of energy, has been experimentally made, 
within the limits of accuracy afforded by observation, and these have 
given rise to some of the most practical of practical results. 
The worker in pure science in physics is dependent upon the man 
of applied science for the instruments required in pushing his work. 
Expensive machinery is required in their manufacture and some of these 
machines exhibit an almost lifelike intelligence, and much more" than 
human accuracy, in the discharge of their duties. The machines for 
making ruled gratings and circles of precision are of this nature. 
In recent years the progress in electric applications and discoveries has 
been so rapid that almost by the time results have been recorded in per- 
manent form the reading resembles ancient history; yet it is altogether 
probable that we have little more than entered upon the field that elec- 
tricity will occupy in the future. A hundred years ago when Volta 
discovered the possibility of producing an electric current he could not 
possibly have dreamed of the wonders it was destined to work, nor could 
Davy have had the faintest idea of the hundreds of thousands of arc 
lamps, which, in the cities of all. the civilized world turn night into day, 
that were to follow his discovery of the electric arc. What would the 
shades of these and other pioneers in electrical discoveries say could they 
see how applied science has harnessed a small portion of Niagara^ enor- 
mous energy and in a city more than twenty miles away, by the mere turn 
of a switch, converts a scene of daylight beauty into perfect fairyland 
