Lieut. Maury's Plan for Improving Navigation. 155 



are carefully examined, and by a very laborious system of 

 trial and error, the combination of squares is found which 

 gives the route most likely to succeed, by ascertaining those 

 through which the loss is a minimum. I s*ay most likely, 

 for of course this is only a problem of chances, and the event 

 may be adverse, as in the case of insurances, but is less 

 likely to be so as observations are multiplied. I should ex- 

 plain that in performing this process, currents and calms are 

 taken into account, and that there are separate compasses 

 drawn, and separate routes traced for each of the twelve 

 months of the year ; for though the winds are assumed to be 

 so far constant for individual months as to give an average 

 on which some reliance may be placed, when the number of 

 observations is sufficiently large, this is by no means the case 

 thoughout the whole year. When the twelve compasses have 

 been delineated and filled up, they are combined, by a pecu- 

 liar and neat arrangement of the numbers within concentric 

 circles, into one, and a chart of the ocean, containing these 

 combinations, is termed a pilot chart. 



" Lieutenant Maury is anxious to obtain at least 100 ob- 

 servations per month in each square, which will be more 

 than a million and a half for the whole ocean, and a less 

 number seems certainly not sufficient to give a result in 

 which confidence can be placed. As might be expected, in 

 some squares he has obtained a great many more than this, 

 and in some none at all ; in the square e. g. which adjoins 

 New York, he has obtained 4,387 observations ; but there 

 is a large space of ocean seldom traversed by ships, that e. g. 

 between the southern extremities of Africa and America, in 

 which the squares are all blank. Now, my Lords, I think 

 those blank squares are a reproach to the civilisation of the 

 present age, and I say so on this principle, that it is our 

 duty not to rest satisfied till we know all that can be known 

 about the globe we inhabit, that can be rendered in any way 

 profitable to our common species ; and therefore I think that 

 the principal maritime nations should share the labour of ex- 

 ploring these vacant spaces, for no doubt shorter routes 

 might be discovered through them, and others matters ascer- 

 tained, to which I shall presently allude. However, it is no 



