6 THREE CRUISES OF THE “ BLAKE.” 
provided with them, and for them as well as for the “Blake ” 
sounding with wire to any depth has become a matter of daily 
routine.” : 
Commander George E. Belknap, U. S. Navy, while com- 
manding the U. S. S. “ Tuscarora,” during her operations in the 
Pacific Ocean, in 1873, was the first to test thoroughly the 
Thomson machine by constant use. While it was evident that 
the machine for sounding by means of wire gave remarkable 
results as compared with rope-soundings, its success was appa- 
rently due in a great degree to the intelligence, patience, and 
skill of Commander Belknap and the officers who assisted him. 
Commander Belknap had always been forced to reel in the 
wire by hand. Among the plans that presented themselves to 
Lieutenant-Commander Sigsbee for the improvement of the ma- 
chine, in order that it might be worked with fewer demands on 
the watchfulness and ingenuity of those having charge of it, 
was the interposition of an aecumulator on the wire, between 
the reel and the sinker, which, by showing the strain on the 
wire at all times during the reeling in, and by easing the sud- 
den jerks on the wire caused by the motion of the ship, would 
allow of reeling in by steam. A machine for experimental pur- 
poses was made in the winter of 1874-5, and the new machine 
(Fig. 3) was used for three years on board the Coast Survey 
Steamer “ Blake," when that vessel was under the command of 
Lieutenant-Commander Sigsbee, and engaged in deep-sea work. 
The following account of the main points of the Sigsbee ma- 
chine is taken from the inventor's detailed description of the 
apparatus in the Bulletin of the Museum of Comparative Zoöl- 
ogy, and its improvements in “ Deep-Sea Dredging : " — 
The reel (A, Figs. 4, 5) should be, for convenience, one 
fathom in eireumference of drum, and should have a friction- 
score which is V-shaped in cross-section. When the sinker 
strikes the bottom, the momentum of the reel and its remaining 
wire requires to be quickly overcome by the resistance of the 
1 But even this excellent sounding the ocean with as great accuracy as we 
machine may soon be superseded by can ascertain the height of mountains 
Siemens’s bathometer, which will en- by a barometer. 
able us to read on deck the depth of 
