54 
BULLETIN OF THE BUREAU OF FISHERIES. 
SOUNDINGS. 
No attempt was made to sound the lakes thoroughly, but where the deepest 
place was not known, which was usually the case, a sufficient number of soundings 
was made to locate the greatest depth. The first rough soundings were made 
in the shallow lakes with a f-inch water-proofed linen line and a 2-pound lead 
weight. The line was checked frequently with a steel tape. On the deep lakes 
a 10-pound lead weight was used on the sounding line, which was checked with a 
steel tape and with the wire sounding machine. It was impossible to get the exact 
depth, as all the lakes change their level during the year, and besides there were 
but few gauges for reference. 
ANCHOR RELEASE. 
During the summer of 1911 the boats from which we worked were anchored 
with a 10-pound folding anchor on all the lakes but Chelan and Pend Oreille. On 
these lakes the samples were taken, without anchoring, on calm days. This proved 
a great waste of time, but it was impossible to haul an anchor from the deepest 
places in these lakes without a power winch. The anchor release described below 
was designed and built to overcome this difficulty, and since it has proved so efficient 
it is described here in the hope that it may be of use to fishermen or others who wish 
to anchor in deep water. 
The anchor release (fig. 2) is made of 3-inch section of f-inch brass pipe fitted 
with a cap. This exactly telescopes into a similar capped piece of 1-inch brass 
pipe. A f-inch hole allows the line to pass through both caps, below which it is 
tied through a rubber stopper. The sections of pipe are held together by a screw 
in the outer section that slides in a vertical slot in the inner section. The inner pipe 
is held up by a small phosphor-bronze spring that must be weak enough to allow 
the weight of the messenger alone to push it down, for in deep water one can not 
tell when the messenger strikes, and if the boat is pulling on the line it will not 
trip until the line is slacked. 
For an anchor a stone weighing from 20 to 60 pounds is harnessed with marlin, 
leaving a small double loop that is placed in the catch of the release. 
The messenger is made of a 2-inch section of 1-inch brass pipe filled with lead 
with a f-inch hole left through the center and a V-shaped slot extending from this 
hole through one side. This allows the messenger to be slipped on the line at any 
place and is much simpler and cheaper than a divided messenger. 
This apparatus can be built for $1, and it has been used with boats from 15 to 
30 feet long in the deepest water of all lakes studied since 1911. 
TEMPERATURE DETERMINATIONS. 
THERMOMETERS USED. 
The determination of temperature, except at the bottom of the deep lakes, 
caused little trouble. A deep-sea Negretti-Zambra thermometer, attached to the 
calibrated sample line, was held at the desired depth for three minutes and tripped. 
The thermometers used in 191 1 and 1912 were not calibrated, but they were compared 
with a standard thermometer in the field and found to agree within 0.2° C. Each 
