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ill；' as the sailors dubbed the paying…out gear； kept grinding away。 'I believe we shall do it this time； Jack；' said one of the crew to his mate。
On the evening of Friday； July 27； the expedition made the entrance of Trinity Bay； Newfoundland； in a thick fog； and next morning the Great Eastern cast her anchor at Heart's Content。 Flags were flying from the little church and the telegraph station on shore。 The Great Eastern was dressed； three cheers were given； and a salute was fired。 At 9 a。m。 a message from England cited these words from a leading article in the current TIMES： 'It is a great work； a glory to our age and nation； and the men who have achieved it deserve to be honoured among the benefactors of their race。' 'Treaty of peace signed between Prussia and Austria。' The shore end was landed during the day by the Medway； and Captain Anderson； with the officers of the telegraph fleet； went in a body to the church to return thanks for the success of the expedition。 Congratulations poured in； and friendly telegrams were again exchanged between Her Majesty and the United States。 The great work had been finally accomplished； and the two worlds were lastingly united。
On August 9 the Great Eastern put to sea again in order to grapple the lost cable of 1865； and complete it to Newfoundland。 Arriving in mid… ocean she proceeded to fish for the submerged line in two thousand fathoms of water； and after repeated failures； involving thirty casts of the grapnel； she hooked and raised it to surface； then spliced it to the fresh cable in her hold； and payed out to Heart's Content； where she arrived on Saturday； September 7。 There were now two fibres of intelligence between the two hemispheres。
On his return home； Professor Thomson was among those who received the honour of knighthood for their services in connection with the enterprise。 He deserved it。 By his theory and apparatus he probably did more than any other man； with the exception of Mr。 Field； to further the Atlantic telegraph。 We owe it to his admirable inventions； the mirror instrument of 1857 and the siphon recorder of 1869； that messages through long cables are so cheap and fast； and； as a consequence； that ocean telegraphy is now so common。 Hence some account of these two instruments will not be out of place。
Sir William Thomson's siphon recorder； in all its present completeness； must take rank as a masterpiece of invention。 As used in the recording or writing in permanent characters of the messages sent through long submarine cables； it is the acknowledged chief of 'receiving instruments；' as those apparatus are called which interpret the electrical condition of the telegraph wire into intelligible signals。 Like other mechanical creations； no doubt its growth in idea and translation into material fact was a step…by…step process of evolution； culminating at last in its great fitness and beauty。
The marvellous development of telegraphy within the last generation has called into existence a great variety of receiving instruments； each admirable in its way。 The Hughes； or the Stock Exchange instruments； for instance； print the message in Roman characters； the sounders strike it out on stops or bells of different tone； the needle instruments indicate it by oscillations of their needles； the Morse daubs it in ink on paper； or embosses it by a hard style； while Bain's electro…chemical receiver stains it on chemically prepared paper。 The Meyer…Baudot and the Quadruple receive four messages at once and record them separately； while the harmonic telegraph of Elisha Gray can receive as many as eight simultaneously； by means of notes excited by the current in eight separate tuning forks。
But all these instruments have one great drawback for delicate work； and； however suitable they may be for land lines； they are next to useless for long cables。 They require a certain definite strength of current to work them； whatever it may be； and in general it is very considerable。 Most of the moving parts of the mechanism are comparatively heavy； and unless the current is of the proper strength to move them； the instrument is dumb； while in Bain's the solution requires a certain power of current to decompose it and leave the stain。
In overland lines the current traverses the wire suddenly； like a bullet； and at its full strength； so that if the current be sufficiently strong these instruments will be worked at once； and no time will be lost。 But it is quite different on submarine cables。 There the current is slow and varying。 It travels along the copper wire in the form of a wave or undulation； and is received feebly at first； then gradually rising to its maximum strength； and finally dying away again as slowly as it rose。 In the French Atlantic cable no current can be detected by the most delicate galvanoscope at America for the first tenth of a second after it has been put on at Brest； and it takes about half a second for the received current to reach its maximum value。 This is owing to the phenomenon of induction； very important in submarine cables； but almost entirely absent in land lines。 In submarine cables； as is well known； the copper wire which conveys the current is insulated from the sea…water by an envelope； usually of gutta…percha。 Now the electricity sent into this wire INDUCES electricity of an opposite kind to itself in the sea…water outside； and the attraction set up between these two kinds 'holds back' the current in the wire； and retards its passage to the receiving station。
It follows； that with a receiving instrument set to indicate a particular strength of current； the rate of signalling would be very slow on long cables compared to land lines； and that a different form of instrument is required for cable work。 This fact stood greatly in the way of early cable enterprise。 Sir William （then Professor） Thomson first solved the difficulty by his invention of the 'mirror galvanometer；' and rendered at the same time the first Atlantic cable company a commercial success。 The merit of this receiving instrument is； that it indicates with extreme sensibility all the variations of the current in the cable； so that； instead of having to wait until each signal wave sent into the cable has travelled to the receiving end before sending another； a series of waves may be sent after each other in rapid succession。 These waves； encroaching upon each other； will coalesce at their bases； but if the crests remain separate； the delicate decipherer at the other end will take cognisance of them and make them known to the eye as the distinct signals of the message。
The mirror galvanometer is at once beautifully simple and exquisitely scientific。 It consists of a very long fine coil of silk…covered copper wire； and in the heart of the coil； within a little air…chamber； a small round mirror； having four tiny magnets cemented to its back； is hung； by a single fibre of floss silk no thicker than a spider's line。 The mirror is of film glass silvered； the magnets of hair…spring； and both together sometimes weigh only one…tenth of a grain。 A beam of light is thrown from a lamp upon the mirror； and reflected by it upon a white screen or scale a fe