Cfiarles Thomas Jackson. — Woodworth. 71 
Morse, the patentee of the magnetic telegraph, to whom there 
is some reason for believing Jackson gave important help in 
his experiments. Once again in Boston, Jackson began the 
practice of medicine, but tinding his services in demand as a 
chemist and mineralogist, he gradually and not against his 
inclination, entered upon a career in these pursuits. He is af- 
terward said to have expressed ss)me regret that he spent so 
much time in the study of medicine. 
The report on Nova Scotia had already given Dr. Jackson 
a name as a geologist and mineralogist. The movement for 
geological surve3's which had led to good results in sev- 
eral of the Sea-board states came in due time to arouse public 
interest in the little known region of Maine. The attention 
of Americans was also called to the importance of the frontier 
of this state by tiie claim of Great Britain to more than ten 
thousand square miles of that tract, the cause of a dispute 
which was finally settled by the treaty of Ashburton in 1S42. 
It served at the time, probably, to stimulate the legislature 
of Massachusetts to co-operate with that of Maine in the 
survey of the public lands owned b}- the former state in the 
latter's territory. As a reminder of the former dejiendence of 
Maine upon the Kay State, we find duplicate reports of the 
survey, which Jackson was now called on to make, addressed 
to the governors of these two States. 
Jackson spent the years 1837-18c{9 in this work. Without 
maps for most of the area, other than those made b}^ himself, 
he traversed the country on lines intended to afford him an 
idea of the dominant features in the topography and geolog3^ 
His reports set forth the places he visited, the sections he 
studied, and the names of the owners of the quarries and pro- 
spective mines whom he either discouraged or helped by his 
advice as the circumstances seemed to him to warrant. We 
find him making a careful stud}' of the intersection of dikes 
to determine their relative ages, and entering upon generaliza- 
tions with regard to the systems of intrusion. PZverywhere 
he was on the outlook for some ecftnomic advantage which 
might accrue from his labors Xo the state, showing in this the 
peculiar trait of the American geologist under the eniploj' of 
the i^ublic. Many details were recorded evidentlj' for some 
future use, the author not disdaining to jjresent them because 
