Marcu 22, 1912] 
must result by reason of the illness of Pro- 
fessor Ritchey and his chief assistant in 
this delicate and laborious task. In the 
meantime the glass-founders of St. Gobian 
are unremitting in their efforts to secure a 
perfect disk. 
It is with deep regret that the observ- 
atory and the institution are called upon 
to record the unexpected death, on May 24, 
1911, of Mr. John Daggett Hooker, to whom 
the enterprise of the 100-inch telescope owes 
its inception. His intelligent interest in 
and appreciation of the work of the Mount 
a gift of $50,000 in 1906 for the purchase 
of a disk and for the shaping of it for a 
100-inch reflecting telescope. Unfortu- 
nately the difficulties in the way of casting 
so large a disk of glass, together with his 
untimely death, have prevented him from 
realizing his desire to see this telescope in 
use. But if the enterprise succeeds, as now 
seems quite hopefully probable, the observ- 
atory and the institution will be glad to link 
the constancy of his faith in scientific inves- 
tigation to the constaney of the stars by 
means of diligent applications of the 
“Hooker telescope’’ to astronomical re- 
search. 
DEPARTMENT OF TERRESTRIAL MAGNETISM 
The magnetic survey of the globe under- 
taken by this department is proceeding 
effectively on both land and sea. Observa- 
tions of the magnetic elements of declina- 
tion, dip and intensity have been made at 
numerous points on the continents of Asia, 
Africa, Australia, Europe, South America 
and on the Polynesian Islands; while the 
non-magnetic ship Carnegie has secured a 
large quantity of data of immediate prac- 
tical utility to navigation and of still 
ereater importance, doubtless, in their rela- 
tions to the general problem of terrestrial 
physics. 
At the end of the previous fiscal year the 
SCIENCE 
443 
Carnegie was en route from the mouth of 
the Amazon to Rio de Janeiro. After 
visiting the ports of Rio de Janeiro, Monte- 
video, Buenos Aires and Cape Town, she 
arrived at Colombo, Ceylon, June 7, 1911. 
Having started on her present circumnayvi- 
gation cruise June 20, 1910, her arrival at 
Colombo marked the end, approximately, 
of the first year out. During this year she 
traversed upwards of 23,000 nautical miles, 
measuring magnetic declinations at 252 
different points, and dip and intensity at 
172 different points at sea. In addition to 
this work, corresponding complete deter- 
minations were made on land at seven ports 
and intercomparisons of magnetic instru- 
ments were made at three ports. 
Unexpectedly large errors have been 
found almost everywhere, except in the 
south Atlantic Ocean, in the best compass 
sailmg charts now in use. This is espe- 
cially the case in the Indian Ocean, for 
which some recently issued charts are in 
error as much as 4° to 6° in the ‘‘compass 
variations’’ assigned. To meet the press- 
ing needs of mariners for more trustworthy 
charts, the data obtained by the Carnegie 
are promptly furnished to the hydro- 
graphic establishments of the world en- 
gaged in the publication of magnetic 
charts. It appears from the investigations 
of the department that the chief source of 
the errors in existing charts lies in a lack 
of knowledge of the secular variation of 
the magnetic elements. It is worthy of 
note, also, in this connection that observa- 
tions of atmospheric electricity and atmos- 
pheric refraction have been carried on dur- 
ing this voyage of the Carnegie. The im- 
portance of precise navigation in recent 
times gives special interest to the outstand- 
ing uncertainties due to atmospheric re- 
fraction. 
Expeditions for land determinations of 
magnetic data have been made to many 
