SCIENTIFIC NEWS. 



[March ist, li 



great physicist's own words in describing the incident: — 

 " I had sounded," Sir William said, in a communication 

 which we abridge from the Nautical Magazine, " from the 

 La/la Rookh, in the Bay of Biscay, with a lead weight of 

 30 lbs., hung, by 19 fathoms of cod-line, from another lead 

 weight of 4 lbs., attached to one end of a three-mile coil, 

 made up of lengths of pianoforte-wire spliced together, and 

 wound on a light wheel, about a fathom in circumference, 

 made of tinned iron plate. My position at the time was con- 

 siderably nearer the north coast of Spain than a point 

 where the chart shows a depth of 2,600 fathoms, the greatest 

 depth previously marked on the charts of the Bay of Biscay. 

 When 2,000 to 2,500 fathoms were running oft" the wheel, I 

 began to have some misgivings as to the accuracy of my 

 estimation of weights and application of resistance to the 

 sounding- wheel. But after a minute or two more, during 

 which I was feeling more and more anxious, the wheel 

 suddenly stopped revolving, as I had expected it to do a 

 deal sooner. The impression on the men engaged was that 

 something had broken ; and nobody on board, except myself, 

 had, I believe, the slightest faith that the bottom had been 

 reached. The wire was then hauled up, and, after 1,000 

 fathoms had been got in, the wheel began to show signs of 

 distress. I then perceived for the first time (and I felt much 

 ashamed that I had not perceived it sooner) that every turn 

 of the wire, under a pull of 50 lb., must press the wheel on 

 two sides of any diameter with opposing forces of 100 lbs., 

 and that, therefore, 2,240 turns, with an average pull on the 

 wire of 50 lbs., must press the wheel together with a force 

 of 100 tons, or else something must give way. In fact, the 

 wheel did give way, and its yielding went on to such an 

 extent that the last 500 fathoms and the 30 lb. sinker were 

 got in with great difficulty. I was in the greatest anxiety, 

 expecting every moment to see the wheel get so badly out 

 of shape that it would be impossible to carry it round in its 

 frame, and I half-expected to see it collapse altogether and 

 cause a break of the wire. Neither accident happened, and, 

 to our great relief, the end of the wire came above water, 

 when instantly the 19 fathoms of cod -line were taken in 

 hand, and the sinker hauled on board. I scarcely think any 

 one but myself believed the bottom had been reached, until 

 the brass tube, with valve, was unscrewed from the sinker, 

 and showed an abundant specimen of soft, grey ooze. The 

 length of wire and cod-line which had been paid out vvas 

 within a few fathoms of being exactly 2,700 fathoms. The 

 wire was so nearly vertical, that the whole length of the 

 line cannot have exceeded the true depth by more than a 

 few fathoms." 



Since the possibility of using steel wire for soundings 

 was thus proved, the system has been introduced with 

 success in a variety of situations, such as scientific in- 

 vestigation (notably during the C/;a//(;;;^er expedition), cable- 

 laying, and hydrographic work generally. By no one, how- 

 ever, has the system been carried to greater perfection than 

 by the officers of the United States Coast and Geodetic Sur 

 vey Department ; and it is to labours of American en- 

 quirers that we now propose to turn our attention. 



The sounding apparatus originally devised by Sir William 

 Thomson was, it is hardly necessary to say, excellently 

 planned to answer the purpose for which it was required. At 

 the same time it was necessarily capable of higher develop- 

 ment, and was afterwards improved by Sir William himself. 

 We do not propose to follow the successive stages through which 

 the apparatus passed, but will at once proceed to describe the 

 sounding machine of Captain Sigsbee, of the United States 

 Navy, illustrated on pp. 3 and 5. The first of these illus- 

 trations is a perspective view of a Sigsbee sounding machine, 

 rigged for reeling in. It is taken from a photograph kindly 

 furnished by the U.S. Coast Survey Department. This, it will 



be seen, has not a steam engine fitted to it, but the other 

 illustration shows a side elevation of a similar machine, 

 with a small oscillating steam engine attached. This illus- 

 tration is taken from a drawing, for which we are indebted 

 to the United States Fish Commission. 



In sounding with wire, the great thing to guard against 

 is kinking. Every one knows how a piece of springy wire, 

 if straightened out after it has been wound on a reel, will 

 immediately assume the form of a coiled spring when the 

 tension which held it straight is released. The steel 

 sounding wire has necessarily a high percentage of carbon, 

 in order to give the required strength, and it is therefore 

 very elastic and springy. When the wire is wound in on 

 the sounding reel, after taking a cast, it is wrapped round 

 with considerable force, as was shown by Sir William 

 Thomson's first reel giving way. From this it follows that 

 the wire must always be kept taut — to use the proper 

 nautical expression — for if the least slackness be allowed it 

 will " throw a turn," which, on the strain being again 

 applied, will form a kink. Such a kink is invariably a 

 source of weakness, reducing the strength of the wire about 

 75 per cent, or more, and therefore always leads to a breakage 

 sooner or later. If soundings were taken from an immov- 

 able platform, the difficulty might readily be met ; but 

 unfortunately a ship's deck is never even approximately 

 stationary, unless the sea be exceptionally calm. This prob- 

 lem, therefore, has to be solved. The weight, or sinker, 

 attached to the end of the wire — or rather to the stray line 

 which in turn is spliced on to the wire — must not be so 

 heavy that it will part the wire when an additional strain 

 is caused by the ship rolling or scending* from the sinker ; 

 but at the same time it must be of sufficient weight to keep 

 the wire under tension when the ship rolls or pitches to- 

 wards the sinker. In the original sounding machine! the 

 wire ran directly from the reel into the sea, and there- 

 fore a considerable surplus of strength over that neces- 

 sary to bear the mean stress had to be provided. The 

 problem Captain Sigsbee set himself to solve was how 

 to equalize the strain on the wire, and the manner in which 

 he accomplished this will be best explained by describing 

 his machine. Referring to the outline drawing on page 5, 

 A is the bed-plate on which the operative parts are mounted, 

 B is one of two pillars which support a frame, on which the 

 pulley (C) runs. The perspective view on page 3 plainly 

 shows both pillars. D is the reel or drum on which the 

 wire is wound. The outline drawing shows the machine 

 rigged for paying out, whilst the perspective view shows it 

 arranged for reeling in. The paying out is naturally the 

 first operation, and we will therefore describe that to begin 

 with. The stray line having been spliced to the wire, the 

 former is passed over the pulley (C) through a swivelling 

 fair leader chock (F). The weight, or sinker (E), is then 

 attached. The next operation is to reeve the brake, or 

 friction-line ; a portion of the apparatus which plays an 

 important part in the working. It is marked G G in the 

 drawing, and passes over a score attached to the outer rim 

 of the reel. The two balances (H H) are for showing the 

 brake-power applied by the line, and are not absolutely 

 necessary to the working of the machine, so their presence 

 may be ignored for the present. The line is next rove 

 under a small pulley at the foot of the pillar. This is shown 

 partly by dotted lines. It next passes upwards between 

 the pillars, and is again rove through a small pulley on the 

 lower part of the frame in which the sounding wire pulley 

 (C) is mounted. From thence it descends and is made fast 



* Scending is the upward motion Of the ship'in a fore and aft direction. 



t This machine was illustrated on p. 41 of the twentieth volume 

 of Engineering. 



