4 INTRODUCTION. 



Oltmanns, &c., we were indebted for the proximate situations of many 

 points of Spanish America. These have again been adjusted by English 

 and United States Officers. 



The more noted of the numerous surveyors who have seconded these 

 scientific leaders in the completion of our hydrographic representations, 

 will be alluded to in connection with their respective labours hereafter. 



While we can refer with confidence to the charts of the various coast- 

 lines, as being so perfect, that no possible alteration will be made in the 

 fixed features of the land, which could be rendered applicable upon a 

 general chart, there is one branch not so satisfactory, though much has 

 been done to remedy this. This is the list of detached dangers, as rocks 

 or shoals, which have been from time to time reported, and which, unless 

 disproved, are a constant and daily source of great anxiety to those who 

 have to pass their vicinity. To deal with the conflicting and ambiguous 

 statements recorded, is most perplexing. Still it is most essential that no 

 danger should remain unmarked, although its existence or situation may 

 be involved in great doubt. It is of the utmost importance, therefore, to 

 the facility and safety of navigation, that these dangers should be correctly 

 placed and characterized, and in the case of a fresh discovery, some test, 

 as by the sounding lead, ought to be applied, to determine its absolute 

 existence. This is now most imperative ; without such guarantee, any such 

 announcement is next to worthless, as being authentic, and most mis- 

 chievous, as leading to distrust and anxiety. All that we know of this 

 subject is recorded in a later part of this work, and in the chart, but it 

 may be stated that of late the extended practice of deep-sea soundings, has 

 actually disproved the existence of many apparently well-authenticated 

 dangers, and thrown very great doubt upon others. 



Notwithstanding the great improvements made in recent times in the 

 appliances placed at the disposal of the marine surveyor for the prosecution 

 of his researches, perfection has not yet been obtained in the results. It 

 is only necessary to refer here to such recent events as the stranding of 

 H.M.S. Sidtan in Comino Channel, Malta, on March 6th 1889, and of 

 H.M.S. Victoria, at Dragomesti, on the coast of Greece, on January 29th, 

 1892, as examples of what defects in the work of the surveyors may lead 

 to. In broad daylight and clear weather these fine vessels were both run 

 aground on uncharted dangers, blind confidence having apparently been 

 placed in the charts used in their navigation. From these, and similar 

 cases mentioned hereafter, the moral may be deduced that no chart can 

 be considered as absolutely perfect, and the mariner should exercise 

 some amount of common sense in their use, especially when navigating 

 in localities with which he is not familiar. 



It has been before stated that the length of the coast-line of the North 

 Atlantic Ocean, between the Arctic Circle and the Equator (excluding the 

 Mediterranean), is about 62,000 miles, more or less. This estimate is 

 higher than has been usually attributed, but it is the result of a measure- 

 ment around the present surveyed coasts, omitting the minor sinuosities 

 and smaller islets. If these were taken into the account the sum would 

 be much greater, as may be supposed, upon an examination, for example, 

 of the vast range of islets which front the coasts of Norway and Tiuland, 



