Mr. J. N. Hearder on the Atlantic Cable. 27 



the composition of the two resultants is a harmony, more or less 

 agreeable, according to the simplicity of the ratio of the values 

 of X. This effect, it appears, is independent of the resulting 

 phases. But the component vibrations of each note may also 

 be grouped according to the values of c ; and assuming these 

 values to be quam proxime consecutive, the number of the groups 

 may be very numerous ; and two may be selected, one from each 

 set, such that the maxima or minima of their condensations shall 

 be very nearly coincident at equidistant points along the line of 

 propagation. The resultant of these two groups will stand out 

 by this circumstance from all the other resultants of two groups j 

 and a musical ear might detect the periodicity from its promi- 

 nent character, although this resultant might not be more 

 audible than the others. In this manner the theory accounts 

 for a perfect consonance being accompanied by Tartini's beats, 

 or grave harmonic, for the constancy of this occurrence, and for 

 the small intensity of the sound. This evidence, that sound- 

 vibrations are compounded like light-vibrations, is sufficient to 

 meet an objection to the proposed theory of the composition of 

 light on the ground of a supposed diversity between light and 

 sound in this respect. 



Cambridge Observatory, 

 December 13, 1858. 



IV. On the Atlantic Cable. 

 By J. N. Hearder, Electrician, Plymouth^. 



THE suspense and anxiety occasioned by the present unsatis- 

 factory condition of the Atlantic Telegraph Cable, have 

 afforded opportunity for an endless amount of speculation as to 

 the cause of failure, and the prospect of ultimate success, and for 

 an infinite variety of propositions for new forms of cable, in- 

 tended to prevent the liability to accident aud remove the 

 objectionable peculiarities of the present one. These have in- 

 cluded some of the most ridiculous schemes that could well 

 emanate from individuals quite unacquainted with the subject. 



During the last twelve months the journals have been teem- 

 ing with notices of new patents, many of them for the revival 

 of contrivances which have long become obsolete, but which 

 ajjpcar, nevertheless, to be quite new to the present projectors. 

 Some have gone so far as to patent impossibiUties, whilst others, 

 better informed, have introduced some valuable improvements. 



In the cure of any disease, it is generally admitted that the 

 discovery of its cause is half the battle; and it will be the 



• llead at the Plymouth Institution and Devon and Cornwall Natural 

 iUbtory Society, December Uith, I8i>8. Commuuicutcd by the Author. 



