ManrcH 22, 1901.] 
extensive surveys in the forested mountain- 
ous region west of the Hudson, the High- 
lands. To this experience he added that 
of service during one winter with a Coast 
Survey party in the Gulf of Mexico. 
The outbreak of the Civil War found 
him, at the age of twenty-five, established 
as a trusted leader among his associates. 
Enlisting as a private, he was followed by 
a number of those who had known him as 
a Surveyor, and he was mustered into ser- 
vice as 1st Lieutenant, Company A, New 
York Volunteer Engineers, September, 
1861. He served until the fall of 1864, 
when he resigned at the request of his par- 
ents after the death of his brother, Lieut. 
J. H. Brooks, in the trenches before Peters- 
burg. 
Major Brooks, as he was generally called, 
although he reached the rank of Brevet 
Colonel, won conspicuous recognition as a 
military engineer at the sieges of Fort Pu- 
laski and Fort Wagner. His industry was 
indefatigable, his engineering talent mani- 
fest, his courage, devotion and self-sacrifice 
unfailing. 
After a year with the New Jersey Geolog- 
ical Survey, in August, 1865, Major Brooks 
accepted a position as vice-president and 
general manager of the Iron Cliff Mine near 
Negaunee, in the Marquette iron district, 
LakeSuperior. Therewith his more impor- 
tant work in geologic research may be said 
tohavebegun. Thegeology of the Lake Su- 
perior Basin had previously been scanned by 
Foster, Whitney, Houghton, Logan, Agas- 
siz and others, and the Laurentian, Huron- 
ian and Silurian systems had been vaguely 
distinguished; but the pressing problems 
of the geology of the iron ores and related 
formations remained untouched. The diffi- 
culties of investigation in that district are 
even now very great. Forest, windfall and 
underbrush make the physical labor of ex- 
ploration severe ; drift mantles wide areas, 
and the relations of the folded, refolded, 
SCIENCE. 
461 
squeezed and metamorphosed formations 
are extraordinarily intricate. Settlement 
of the wilderness, extensive prospecting and 
mining operations and the development of 
modern petrographical methods have made 
a solution of these relations possible, but 
when Brooks faced them the difficulties 
were unequaled, the means and methods 
sadly inadequate. Nevertheless, he at- 
tacked them with characteristic energy and 
originality. He invented methods, he pro- 
vided means, he spent himself, and he 
achieved the greatest measure of success 
then possible. In general geology he con- 
tributed important data and conclusions on 
the great geologic systems and the uncon- 
formities which separate them. In theo- 
retical geology he first suggested that sec- 
ondary deposition might be the genetic 
condition of the iron ore bodies. But it 
was in applied geology that he made his 
chief contribution, one in which he found 
most satisfaction, and one for which not 
only Michigan is his debtor, but also the 
people of the United States. Our coun- 
try’s iron and steel industry, our machine 
shops, our railway systems, and all the 
wonderful material conquest of the conti- 
nent have been greatly promoted by exploi- 
tation of Lake Superior iron ores. Brooks 
took hold of that exploitation in its begin- 
ning, and he had a leading part in its de- 
velopment. Simple methods were needed 
of surveying in the unbroken forest amid 
widely varying magnetic attractions. 
Brooks devised the dial compass and 
taught men to pace distances in the most 
tangled underbrush. Magnetic surveys 
were necessary aS a means of prospecting. 
Brooks adapted the dip needle to the capa- 
city and purposes of the prospector. Men 
wanted practical advice based on scientific 
principles. Brooks harnessed his practise 
and his science together, and thus became 
the most reliable mining engineer, as well 
as the most useful geologist, in the region. 
