Chftrles 71io)nas J(icks<)n. — Wood irorlh . 81 
ment of his interest in the science, thotigh liis work is more 
limited in its scope, being mainly mineralogical and chem- 
ical. His work in mineralogy was of a character to link 
his name in one way or another with several minerals. 
Masonite which he named and described in the Rhode Is- 
land report is regarded by Dana as an impure substance 
and is referred to chlorotoid. It was rather his own fault 
than professor Whitney's that Jackson's name is not 
borne by one of the Lake Superior minerals. Jacksonite 
was proposed by Whitnej^ for a supposed hj^drous prehnite 
from Keweenaw Ft. and Isle Royale. Dr. Jackson, with his 
accustomed method of procedure in such cases subjected this 
mineral to analj'sis and found that it was lacking in the re- 
quirement of water, a conclusion with which Dana concurred. 
Jackson appears to have been tlie first to observe the occur- 
rence of tellurium and silenium in America. He was al^o.the 
first to report amazon-stone (1859). His geological inquiries 
led him into the field of mineral genesis, and we find him bold- 
ly demanding a deepseated origin for substances then thought 
by many to be due to the selective action of organic life. Phos- 
phate of lime, he argued, is not necessarily of organic origin, 
since it is found in igneous dikes. For the same reason he 
concludes that phosphorus is an element in the interior of the 
globe. 
Perhaps his most important work in mineralogy was eco- 
nomical in its character. The emery mines of Massachusetts 
remain a monument, hollow and inverted, it is true, to his a- 
cumen in this field of research. As he himself states, this lo- 
cality was found by Dr. H. S. Sears, but it was Jackson's pai-t 
to develop the real value of the locality. From the minerals 
already known there, he inferred the existence of emery and 
found it. Up to that time, a London banking house controlled 
the only workable d(?posits of this variety of corundum, those 
of the Grecian archipelago. 
His exploitation of the lean ore bands of New England de- 
served better success to himself and to land owners than have 
accrued in the years since traces of metals were discovered in 
this area. Numerous were the rumored occurrences of tin, 
gold, and other useful ores which he diligently ran down and 
investigated in hopes of their proving of industrial impor- 
