THE SEA AND THE ATMOSPHERE. 21 



independent of these facts and views, there is another reason Avhy 

 iron wrappings and two metals should not he nsed, at least for 

 deep-sea cables. Our researches at sea have shown that there is 

 no running water at the bottom of the deep sea. Hence we infer 

 that a telegi-aphic cord once lodged on the bottom of the ocean, 

 there, as the tree that falls in the forest, it would lie; for there 

 is nothing to disturb it more. Wherefore it has been held,* that 

 the iron wrapping for deep-sea lines of telegraph, instead of 

 being advantageous in any aspect, are not only a hindrance, 

 but an incumbrance also and a waste : the weight of the cord 

 may be adjusted to sinking by the size of the conducting wire 

 within as well as by the character of the non-metallic wrapping 

 without. 



(jG: Bogerss cable '^JacJcet." — Whether the insulating material 

 be gutta-percha, india-rubber, or other matter, it requires to be 

 protected from chafes and bruises while on board, and when it is 

 being payed out. And it may be so protected by a covering, not 

 of wire, but of silk, hemp, flax, or cotton. An ingenious Ame- 

 ricanf has invented a "jacket," which will not only protect the 

 cable while on board, but afterwards also, and when it is at the 

 bottom even in shallow and running water. Thus one of the 

 obstacles which have been interfering with the progress of sub- 

 marine telegraphy is removed out of the wa}^. 



67. Deep-sea temperatures a desideratum. — But notwithstandino* 

 all that has been done with the sea and in the sea for the electro- 

 magnetic telegraph, and for human progress, there still remain 

 many agenda. There is both room and need for further research, 

 more exploration, and many experiments. As bearing upon 

 the Dest insulating material for submarine lines of telegraph, a 

 good series of deep-sea temperatures is mucJi needed. Of all 

 those who are now engaged in observing and studying with us, 

 and for us, the phenomena of the sea, are there none who will 

 make deep-sea temperatures a speciality ? They would no doubt 

 prove as instructive and as useful too as deep-sea soundings have 

 been and are. 



* Vide Letter to Secretary of the Xavy, November 8, 18oG. Maury's 

 Sailing Directious, chapter Subjiaeixj: Telegraphy ; ditto, Physical Geography 

 of the Sea, chapters XIII. and XXI. Harper Brothers, New York, 1859 ; also 

 Journal Eoyal Dublin Society, numb .rs XII. and XIII. Letter to John Locke, 

 on the Athmtic Telegraph causes of failure and probabilities of ultimate suc- 

 cess. Eead Januaiy, 1859. 



t Henry J, Rogers of Baltimore 



