448 
occupied in common by the two surveys, as 
given by Hayden and Wheeler, the determina- 
tions of the former preceding : — 
——— SSS . *1 
ee endieaeaae. Loneitndes of the Wheeler work was very similar to that 
% Uae a, ei . of the Hayden survey, except that the adjust- 
; ments were made by least squares. 
42° 57’ 10.6 | 112° 10’ 97.4 
Putnam, Idaho . 7 42 88 8 .0| 112 10 10 20 Henry GANNETT. 
Ds) y 5 3 
Preuss (Meade), Idaho . .} e a rf 5 aa iz i _ 
(| 42 27-53 .7 | 111.38. 41 
Soda (Shennan), Tahoe « «+ -/) 42 27 52.0} 1138110 THR DEEP-SEA DREDGING APPARA- 
Lyle 43 5 86 .2| 111 18 56 27 | 
Caribou (Pisgah), Idaho | 43 ; 34 (0 | 111 18 58 i TUS OF THE TALISMAN.} \ 
ee ae eat Hoy | 40 2t 44 9 | 111 57 Saleen 
Poland Merth Ogden), Utah’ -)) at 21 45 10°} 119 67 Some Tne first French deep-sea exploring expedition was 
The following are the differences between 
the two sets of results : — 
| DIFFERENCES. 
STATIONS. | 1 eee. = 
SCIENCE. 
lines, was done by one party in six field-sea- 
sons, each of four months’ duration. As a 
rule, all the work upon a station was com- 
pleted in a few hours. The general character 
made in 1880 by the Travailleur, in the Bay of Biscay. 
The following year the Travailleur was again put at 
the disposal of the commission over which Mr. Milne- 
Edwards presided; and the party traversed the Bay 
of Biscay, visited ‘the coast of Portugal, passed the 
Strait of Gibraltar, and explored a large part of the 
ee: mieede. i TLonettace Mediterranean. - In 1882. the- same vessel: undertook 
= =a a third expedition into the Atlantic Ocean, and pro- 
Putnam . : , 2/7.6 ; 07.6 ceeded as far as the Canary Islands. But the Tra- 
as i eee a ee vailleur, being a despatch-boat for harbor use, did not 
Caribou . MN Om omen | yal ve possess the requirements for making long voyages; 
Willard . 3 | Opal Ot 
The average differences are respectively 1.6 
and 0”.5. 
It is to be regretted that the distances be- 
tween these points, as determined by the 
Wheeler survey, are not availa- 
ble, in order that a more direct 
comparison might be made. 
It should be understood that 
the object of each of these sys- 
tems of triangulation was sim- 
ply and solely to furnish ade- 
quate control for topographic 
work, to be published on a scale 
of four miles to an inch, or |. ae 
about sspooo: A greater de- See 
gree of accuracy than was re- 
quired for this purpose was not 
contemplated. In all cases 
natural points were used as sig- 
nals until the stations were 
occupied, when rude cairns of 
Nes Acores 
< Fayal® & 
and accordingly the Talisman, a cruiser, was equipped 
for a new dredging expedition, and left the port of 
Rochefort on the 1st of June, 1888, with Mr. Milne- 
Edwards and the commission appointed by the min- 
ister of public instruction on board. The Talisman 
explored the coasts of Portugal and Morocco, visited 
the Canaries and Cape MOS: traversed the Sargasso 
QJ’ BL. qual. 
Pico i 
AITLANT\|I PUE 
13 Madera) &, 
Hoge 
Tdnzarotie. 
Tener 72, 
lles io < 
Canaries 
[Vou. IIL, No. 62. 
stone, six to eight feet in height, 
were erected, and used there- 
after as signals. The Hayden 
work was carried on with an 
4550 
4615 
st Intanu, a ff, a 
SVineent x ‘ ae 
Iles du Cap Vert -X C Port) Li: 
gf 
eight-inch theodolite, reading 
ee 10”; and the work was ad- 
justed by a graphic method, with 
foresights only. The area triangulated by this 
survey aggregated nearly a hundred and twenty 
thousand square miles; which work, besides. 
the measurement and expansion of four base- 
Fie. 1.— Course of the Talisman. 
Sea, and, after remaining some time at the Azores, 
returned and explored the Bay of Biscay (fig. 1). 
On the bridge of the Talisman there had been 
1 Condensed from an account in La Nature. By H. Finaon. — 
