The release takes place in the following manner:  when all the cylinders have been lowered to the required depths, they are left hanging for a few minutes, so that the thermometers may be set at the right temperature before the column of mercury is broken.  Then a slipping sinker is sent down the line.  When this sinker strikes the first apparatus, a spring is pressed, a hook (e) which has held the cylinder slips loose, and the cylinder turns completely over (Apparatus I.).  As it does this, the valves, as already mentioned, close the ends of the cylinder, which is fixed in its new position by a hook in the bottom of the frame.  At the same instant the slipping sinker that hangs under Apparatus I. is released, and continues the journey to Apparatus II., where the same thing happens.  It is then repeated with Apparatus III.  When they are all ready, they are heaved in.

By holding one’s finger on the line one can feel, at all events in fairly calm weather, when the sinkers strike against the cylinders; but I used to look at my watch, as it takes about half a minute for the sinker to go down 100 metres.

The necessary data are entered in a book.

On the morning of the 17th, then, the sails were clewed up, and the Fram began to roll even worse than with the sails set.  We first tried taking soundings with a sinker of 66 pounds, and a tube for taking specimens of the sea-bed.  At 2,000 metres (1,093 fathoms) or more the line (piano wire) broke, so that sinker, tube, and over 2,000 metres of line continued their way unhindered to the bottom.  I had thought of taking samples of water at 4,000, 3,000, and 2,000 metres (2,187, 1,639, 1,093 fathoms), and so on, and water-cylinders were put on from 0 to 2,000 metres.  This, however, took six hours.  Next day, on account of the heavy sea, only a few samples from 0 to 100 metres (54 fathoms) were taken.  On the third day we made another attempt to get the bottom.  This time we got specimens of the sea-bed from about 4,500 metres (about 2,500 fathoms); but the heaving in and taking of water samples and temperatures occupied eight hours, from 7 a.m. till 3 p.m., or a third part of the twenty-four hours.  In this way we should want at least nine months on the route that had been laid down; but as, unfortunately, this time was not at our disposal, we at once gave up taking specimens of the bottom and samples of water at greater depths than 1,000 metres (546 fathoms).  For the remainder of the trip we took temperatures and samples of water at the following depths:  0, 5, 10, 25, 50, 75, 100, 150, 200, 250, 300, 400, 500, 750, and 1,000 metres (0, 2 3/4, 5 1/2, 13 1/2, 27, 41, 54, 81, 108, 135, 164, 218, 273, 410, and 546 fathoms), in all, fifteen samples from each station, and from this time forward we went on regularly with one station every day.  Finally, we managed to heave up two water-cylinders on the same line by hand without great difficulty.  At first this was done with the motor and sounding-machine, but this took too long, and we afterwards used nothing but a light hand-winch.  Before very long we were so practised that the whole business only took two hours.