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depths, was a common houfhold pail or bucket, with 
two heads in it ; which heads had each a round hole 
in the middle, near four inches diameter, which were 
cover’d with valves which open’d upwards ; and that 
they might both open and fhut together, there was a 
fmall iron rod fixed to the upper part of the lower 
valve, and at the other end to the under part of the 
upper valve : fo that, as the bucket defcended with 
its finking weight into the fea, both the valves open’d 
by the force of the water, which had by that means 
a free paffage thro’ the bucket. But when the bucket 
was drawn up, then both the valves were fhut by the 
force of the water at the upper part of the bucket i 
by which means the bucket was brought up full of 
the lowed: fea-water, to which it had defcended. 
When the bucket was drawn up, the hole at the 
bottom was flopped with a cork, to keep the water 
in, when the valves were open’d, to come at the 
mercurial thermometer, which being tied to an up- 
right flick, could readily be unfaflened, by pulling 
out a loofe nail, which went into the upper end of 
flick, which was faflen’d at its lower end in the fame 
manner. 
But great care mufl be taken to make an obfer- 
vation of the degree the mercury Hands at, before 
the lower part of the thermometer is taken out of 
the water; elfe it would immediately be alter’d by 
the different temperature of the air. 
In order to keep the bucket in a right pofition,, 
there are four cords fixed to it, which reach about 
three feet below it, to which the finking weight is to 
be fixed. 
Captain 
