764 SCIENCE. 
year, and has a very extraordinary passion for 
physico-mathematical sciences. * 
In the autumn of 1825, with his younger 
brother, Henry, he went to Baltimore, and 
there, for a time, pursued various vocations 
including that of scientific advisor to Isaac 
Tyson, the chemical manufacturer, but 
chiefly that of teacher in a school estab- 
lished by the two young men in Windsor. 
The pursuit of science was the aim of his 
ambition, and he was fortunate in securing 
an appointment, early in 1827, to deliver a 
course of lectures before the Maryland In- 
stitute. These were so successful that he 
gave a second course a year later. Con- 
cerning these Henry wrote to his father : 
William is still able to command large and 
ever increasing classes. * * * I cannot refrain 
from expressing my surprise at William’s great 
success, aided as he is by little more than the 
blackboard and chalk.+ 
Walker said of these lectures that he then : 
First displayed upon an adequate field, that 
power of clear exposition felicitous illustration 
which he possessed in a degree, perhaps, never 
excelled. { 
In August, 1828, came the death of the 
elder Rogers, and two months later William 
was chosen his father’s successor in the 
chair of natural philosophy and chemistry 
in William and Mary College, ‘‘ and thence 
forward became, in a large measure, the 
head of the family.’’§ For some years he 
continued in the active possession of that 
chair, also during part of the time tempor- 
arily filling the chair of mathematics. His 
professorial duties were naturally para- 
mount, but it must be noted that at that 
time he published a paper on Dew, and with 
his brother Henry one on the Voltaic Bat- 
tery, both of which were subjects directly 
connected with his professorship. 
* Life and Letters, p. 26. 
tT Idem, p. 47. 
} Biographical Memoirs, p. 3. 
@ Life and Letters, p. 54. 
[N. S. Von. X. No. 256. 
Of subjects less directly associated with 
his college duties, to which he devoted 
much attention, were topics connected with 
geology. He wrote a series of articles on 
the Green Lands and Marls of Eastern 
Virginia, describing their value as fertil- 
izers, and says Cooke : 
Next we find the young professor going be- 
fore the legislature of Virginia, and, while mod- 
estly presenting his own discoveries, making 
them the occasion for urging upon that body the 
importance of a systematic geological survey 
for developing the resources of the State. 
The year 1835 saw the culmination of his 
ambition in that respect, for in March he 
was appointed director of the Geological 
Survey of Virginia. 
As was anticipated, says Cooke : 
The survey led to a large accumulation of 
material, and to numerous discoveries of great ~ 
local importance. As this was one of the earliest 
geological surveys undertaken in the United 
States, its directors had, in great measure, to 
devise the methods and lay out the plans of in- 
vestigation which have since become general. 
* * * [Also] there are four or five general re- 
sults of Professor Roger’s geological work at 
this period, which have exerted a permanent 
influence in geological science.* 
These general results included the study 
of the solvent action of water in various 
minerals and rocks ; the demonstration that 
coal beds stand in close genetic relation to 
the amount of disturbance to which the in- 
closing strata have been submitted; the 
announcement and discussion of the wave 
theory of mountain chains ; and the law of 
distribution of faults. In working out 
these subjects and in the presentation of 
papers discussing them he was associated 
largely with his brother Henry, who was at 
that time State Geologist of Pennsylvania. 
It has been well said that ‘‘ together they 
unfolded the historical geology of the great 
Appalachian chain.”’ 
* Notice of William Barton Rogers, p. 429. 
