March 1, 1887.] 



KNOWLEDGE ♦ 



101 



instance, the following stitcment in Professor Hughes's ex- 

 cellent little work on the construction of maps, a statement 

 for the accuracy of which I can answer, having indepen- 

 dently tested the matter : " In the case of a voyage from 

 the mouth of the English Channel to New York, supposing 

 a due west or adverse wind to last during the entire voyage, 

 and pi-esiiming a ship to advance at the rate of 150 miles a 

 day, the length of time occupied by her following through- 

 out the tack nearest to the rhumb course (or that which 

 would be pursued in the ordinary practice of navigation) 

 would be forty-nine days, while by pursuing the tack nearest 

 to the great circle course, the time would be diminished to 

 forty-three days eight hours — the distance passed over being 

 in the former case 7,3(Jl miles, and in the latter G,-t88 

 miles, a difference of 873 miles in favour of the great circle 

 course." 



It may surprise the reader perhaps to learn that, in such 

 a journey as Professor Hughes has here considered, the 

 "practical" seaman of the old school, who refuses to be 

 troubled by " great circle nonsense," and sticks to his rule of 

 thumb rhumb rules, will on certain parts of his course be 

 actually increasing his distance from his port, by sailing as 

 close as he can to the rhumb track pencilled on his chart. 

 For example, suppose him ofl" the Lizard ; his rhumb course 

 for New York, a straight line on !Mercator's chart, woiild lie 

 west-south-west ; his shortest or great circle course would 

 lie about west by north. Suppose now that the wind is 

 about west-south-west, and that the ship cannot sail nearer 

 than six points to the wind, then the proper course to 

 pursue is to make long tacks to the north-west, only three 

 jioints from the true great circle course, and short tacks to 

 the .south, in which a certain amount of distance is lost. 

 But the practical old sea-dog who sticks to his rhumb line 

 will take equally long legs to the north-west and to the 

 south, supposing each to be about six points from his true 

 course, whereas on every southern tack he is nine points 

 from his true course to New York and only seven points 

 from his true course home. Such is the practical effect of 

 too strong a hatred of new-fangled ideas. 



Jlr. Froude remarks of the seeming departure of the 

 Australasia from the straight-line track on the chart that, 

 had the passengers been required to give their independent 

 opinions, they would have voted " that we were going wrong, 

 and must change our direction, especially if they suspected 

 that the captain and otiicers were interested in the matter. 

 They were not asked for their opinions, and did not wish to 

 give them. They were contented, being ignorant, to be 

 guided by those whom they supposed to know," on which he 

 makes the i-ather odd comment, " This is the universal rule, 

 and when it is observed our sums woi'k out clear without 

 fractional remainders." 



This trust in the supeiior knowledge of the officers who 

 direct a ship along the shortest route is especially taxed 

 when long journeys have to be taken in high latitudes. For 

 instance, imagine the state of mind of a passenger who, 

 having opened his Mercator's map, had traced out thereon 

 the track from Cape Agulhas to ilelbourne, and found, at 

 the end of the first day out, that the captain was taking the 

 ship to the south-east instead of nearly due east as the map 

 seemed to indicate. If perchance the passenger were a flat- 

 earth man, and had provided himself with one of those 

 ingenious maps in which Mr. Hampden (following the 

 deceased Newton of the flat-earth folk, " Parallax"), pre- 

 .sents the earth in cart-wheel form with the north pole as its 

 centre, and the south polar regions around its circumference, 

 the case woidd be even worse. For, drawing a straight line 

 from the Cape to Melbourne on such a chart, the unhappy 

 paradoxist passenger would recognise as the shortest track 

 to Melbourne a course running considerably north of east, 



and the perversity of the captain in running considerably 

 south of east would seem still more disastrously mistaken. 



It may be imagined how far the shortest or great circle 

 course may be from any such track as a chart would show 

 as such, that if one were starting from England to China 

 on a great circle course one wo'.ild go neither to the east nor 

 to the west, but nearly due north. So if one were starting 

 from Cape Town to New Zealand, one would go neither east 

 nor west, but nearly due south. 



As a matter of fact, the actual great circle course in such 

 cases cannot be pursued. The assaults made in former times 

 on the problem of the north-western passage iirobably in- 

 volved some perception of the fact that an Arctic journey, 

 if practicable, was the best w-ay to reach India ; though a 

 north-eastern jiassage, such as Nordenskjiikl has accomplished, 

 would be better than a north-western one, if both were not 

 so difficult and dangerous as to be utterly useless, at least 

 as ways to the Pacific Ocean. But even such moderate 

 approach to the Antarctic regions as many journeys in the 

 Southern Ocean would involve, if made along the gi-eat circle 

 course, is in reality so undesirable that it may be regarded 

 as to all intents and purposes forbidden by nature. Con- 

 sider, for example, the following cases of icebergs seen in 

 latitudes not nearly so high as those into which the great 

 circle course from Cape Town to Adelaide or to Melbourne 

 would carry a ship. They are cited by Mr. Towson in a 

 paper on the Icebergs of the Southern Ocean, publi-shed 

 by the Board of Trade : 



On September 10, 18G6, the LigldnUig, when in latitude 

 55° 33' south, longitude 140 west, came across an iceberg 

 420 feet high. 



In February 1850 Captain Clark, of the same clipper, 

 records an iceberg 500 feet high and three miles long, seen in 

 latitude 55° 20' south, longitude 122° 45' west. 



On December 1, 1851), Captain Smithers, of the Edmond, 

 reported an island 580 feet high and from two and a half to 

 three miles long, in latitude 50° 52' south, longitude 

 43° 58' west. This island has not been admitted into the 

 Admiralty charts, like some I know of, which for a time 

 did duty there, but were discountenanced later. And there 

 can be very little doubt that Captain Smithers's supposed 

 island was merely an iceberg of enormous size. Probably 

 the Antarctic tract recorded by Caiitain \Vilkes, of Trent 

 notoriety, and subsequently sailed over by an English ship, 

 was a still more enormous field of floating ice, many miles in 

 length, and averaging nearly a mile in total thickness. 



In January 18G1, five icebergs, one 500 feet high, were 

 met with in latitude 55° 4G' south, longitude 155° 5G' 

 west. 



In the same month, 26' farther south, and 4° 4' farther 

 west, an iceberg 500 feet high and half a mile long was 

 found. 



In April 1864, the Royal Standard came into collision 

 with an iceberg GOO feet in height. 



In December 185G, four large icebergs, one of them 700 

 feet high and another 500 feet, were met with in latitude 

 50° 14' south, longitude 42° 54' east. 



On Christmas Day 1861, pretty near Midsummer Day, 

 too, in the southern hemisphere, the Queen of Nations fell 

 in with an iceberg in latitude 53° 45' south (corresponding 

 to the latitude of Hull or Leeds in our northern hemisphere), 

 720 feet high. This was in longitude 170° west. 



On March 23, 1855, the Agneta passed an iceberg in 

 latitude 53° 14' south, longitude 14° 41' east, OGO feet in 

 height. 



On August 16, 1840, the Dutch ship General Baron 

 von Green passed an iceberg 1,000 feet high, in latitude 

 37° 22' south (corresponding to the latitude of Seville in the 

 north), and longitude 14° 10' east. 



