Miscellaneous. 81 



before the costly machinery of an ocean telegraph can with safety 

 be put in motion. 



" In saying this much, I beg emphatically to disclaim any disre- 

 spect towards the distinguished naval officers who have conducted 

 former telegraphic surveys, and who are known to have performed 

 their duties in the most masterly manner, and in conformity with 

 every requirement understood to exist at the period when the task 

 was entrusted to them. 



" In engineering operations on land, as, for example, the con- 

 struction of a railway, it is customary to effect an accurate survey 

 of the country generally through which the proposed line is to pass, 

 with a view to the subsequent precise definition of the line in ques- 

 tion, and it would be regarded as little short of an act of insanity 

 on the part of a Company were it to define the exact course and' 

 order every appliance for its construction before being furnished 

 with a detailed analysis of the difficulties to be surmounted or the 

 geological character of the surface to be traversed. Yet this is the 

 procedure which was adopted in oceanic telegraphy until a very 

 recent date ; the precise line from point to point having been deter- 

 mined as the jjreliminary step, the cable intended to be laid down 

 having been manufactured without the slightest reference to tho 

 nature of the bed it was destined to rest upon, and the survey for 

 depth having been regarded rather in the light of an accompaniment 

 than an essential condition of the undertaking. 



" Latterly, it is true, the error and risk inseparable from such a 

 system of conducting great telegraphic enterprises have become 

 too palpable to be ignored, and the value of an approximate know- 

 ledge of the constitution of the sea-bed to be traversed has been 

 recognized. But I hope to be able to satisfy the Council that, with 

 all the improvement that has taken place on this score, much still 

 remains to be accomplished, and that several collateral branches of 

 inquiry involving the permanent safety of every submerged cable, 

 in quite as important a degree as those touching the mere depth of 

 water and the composition of the immediate surface-layer of the 

 sea-bed, have heretofore been far too partially investigated. These 

 inquiries, one and aU, are intimately associated with physical 

 geography and the various departments of natural science, and will 

 therefore, I trust, be regarded as legitimate subjects for considera- 

 tion by the body I have now the honour to address. 



" In order to acquire the largest amount of information from the 

 method of survey now proposed, I beg leave to suggest that it 

 should comprise the following heads : — 



" 1. Soundings at such intervals as may be found necessary to en- 

 sure accurate results during the course of the Survey, — for 

 Depth ; for Specimens of Bottom ; and for Depth of Deposits. 



" 2. Examination of bottom with reference to its Mineralogical 

 and Geological Features and Organic Products. 



" 3. Regular observations on Temperature of Sea at its surface, 

 and at stated intervals down to the greatest depths. 



" 4. Observations on Density and Pressure at stated depths. 



Ann, & Mag. N. Hist. Ser. 4. Vol. xviii. 6 



