UM 



K1TBQBOLOOY. 



[OCEAN CUHRCNT*. 



north- wt coast of America. Meteoric conditions like 

 Inch mark the oourae of the gulf .stream, also 

 mark tlie ooune of this. Fogs and mists follow in it* 

 track, and itoruu am also generated on the bank of this 

 oceanic river. 



Fur a fuller account of oceanic currents than is con- 



U with the limit* an.l o!.j.-cU of these pages, w 

 must refer the rvadt-r to treatises which deal with tho 

 special matter, and, above all, to the work of Lieutenant 

 f the United States' service, to whom meteoro- 

 logist* are under deep obligations, for his contribution* 

 to their knowledge of ocean phenomena. 



In contemplating these oceanic currents, of which the 

 gulf stream may appropriately be considered the type, 

 we cannot fail to be impressed with an evidence of de- 

 sign, where, at first, no design would snem to 

 These oceanic currents originate in, and are determined 

 l>y, a peculiar conformation of the land. Now, what can 

 be more seemingly irregular or capricious than the shape 

 of land? If dropped down into the ocean at random, 

 or elevated by a subterranean power equally capricious, 

 the crust line of islands and continents, tho solid blocks 

 of our planetary crust, could not well bo more irregular 

 than they are ; and yet how practically harmonious is 

 tho relation Ix'twecn land and water : how well adjusted 

 the Dowers of each how well adapted to the mutual 



:it of mankind ! It appears an unimportant matter 

 hi-ii, in the map of the world, we skim our eye over the 

 southern hemisphere of the terrestrial globe ; there we 

 behold the limits of the African and American continents 

 in their furthest extent ; but how terribly 

 would the locomotive faculty of mankind 

 have been impeded had either continent 

 expanded itself to the south pole, or even 

 traversed much further south than is actually 

 the case ! 



In connection with the subject of ocean 

 currents, the effect of aqueous temperature 

 on the ocean's denizens, deserves a passing 

 wonl of remark further than has already 

 been devoted to it. In the Caribbean Sea, 

 ami other ocean cauldrons, where stores of 

 heat are accumulated for distribution in 

 regions far away in the hot currents which 



nate in these tepid sources of oceanic 

 rivers, there are a fauna and a flora : the fauna no less 

 marked than we see on tropical lauds. There grows the 

 coral, there swims the shark ; and thousands of shelled 

 inollusca, of gorgeous colour and enormous size, revelling 

 in oceanic forests of rank and bulky growth, represent 

 the land forests, and their denizens of corresponding 

 climes. But, though grandeur aud beauty be the charac- 

 teristics of these warm ocean spots tho thermal oei -in- 

 tropic (if the propriety of that expression bo allowed) 

 it is the colder oceanic currents which support the form 

 of animal life most useful to man. Strange though the 

 circumstance may appear, it is no less true, that tho fish 

 of the hot parts of the world are always indifferent as 

 food. This fact is strikingly illustrated in the Mediter- 

 ranean. The temperature of the Mediterranean water 

 is usually four or five degrees above the temperature of 

 the external ocean ; and what a difference in the fish ! 

 Wh'ievcr has compared the edible fish of the Atlantic 

 with those of tho Mediterranean, will be at no loss to 

 admit the vast superiority of the former. The naturalist 

 does not .bo informed, that not only are 



Mediterranean fish inferior to those of the Atlantic, but 

 they are, for the most part, of different species. 



Let us now take a glance at the locality of the princi- 

 pal fishing regions. Limiting ourselves to two of these, 

 they would uni|U.^tionaUy bo tho fishing-grounds .,!' 

 Newfoundland and Japan. The former is the bettor 



ui of the two, though, perhaps, tho latter is the 

 in.. re considerable, seeing that the natives of Japan are 

 debarred from the use of animal food by their religion, 

 although the cat in-,' of |j ; ,h lioin ; permitted, they are all 



i.vophagi ; and, notwithstanding tho dense popula- 



of the Japanese inlands, their inhabitants, thou di 

 fish-eaters, are abundantly fed. 



Between the gulf stream and tho coast i* a narrow 

 Km.! of cold water: hereare t mid- 



land. Between the China current, as it is denomii 

 and (lowing in an opposite direction, is the col.l v\.- 

 in which the Japanese fisheries are prosecuted. Tln-.se 

 are the two most prominent examples, and they will bo 

 found to present the type of many .> 



COLD, AND ITS 1 1'ndi-r tin' heads of Snow, 



Hail, and Hoar-Frost, some of the meteor..:, 

 eold have been already described. The ph .-nomena due 

 to this powerful agency are, however, so numerous and 

 so important, that it may bo well to make tho su 

 cold a matter of special contemplation. If, casd 

 eye over the field of nature, we endeavour to si ' 

 most prominent results of cold, they will be found t<> re- 

 late to tho departure, from an ordinary law, which 

 has in ide in the expansion of water during the act of 

 free&ng. 



Tho term freezing is but a general expression for the ! 

 act of solidification by cold. Popularly, the term is only 

 applied to solidified water ; but this is altogether a con- 

 ventional acceptation of the word. Wo are justified, 

 then, in comparing the act of solidification of water 

 with the act of solidification of any other fluid, and see- 

 ing to what extent the conditions which regulate one 

 ;nlate the other. 



When the temperature falls to 32 F., water ceases to 

 bo liquid, and becomes ice; the weather is said to bo 

 frosty, and water is said to be frozen. Whatever water 

 bo contained in the atmosphere at tho freezing tempera- 

 Fig, er. 



tnre, is deposited in the solid form of hoar-frost;, the 

 particles not being irregular, but bounded by definite 

 mathematical outlines frequently giving rise to forms 

 of great beauty, especially on win.low-p.uies, bla lea of 

 grass, and leaves (Fig. 67). Theso forms are similar, in 

 general contour, to those of well-formed snow II 

 (Fig. C8), but far more beautiful, and, like snow-ll 

 prove that frozen water is a crystalline body, and that it 

 crystallises in forms belonging to the rhombohedral 

 system. 



But the most important point connected with tho 

 freezing of water, and without which our globe would 

 cease to be habitable, is this : Water, during the act of 



Fig. 68. 



freezing, expands, and thus becomes specifically lighter, 

 loo, therefore, swims on water ; it cannot sink. Howr 

 stupendous are the consequences of this departure from 

 tho law of freezing ! Had it so happened that frozen 

 water, like frozen mercury, were heavier than tho cor- 

 rcsjioii'liir,' liquid material, e.i-h frozen sheet of water 

 wouM sink as soon as formed; and thus, being far 

 removed from the melting iniliienco of solar ra . 

 production of ice would have been accumulative, and tho 

 ...'.in, long ere this, would have been com 

 ice-locked. 



In tracing, hypothetically, an assumed aberration of 

 Nature to its consequences, tho mind is speedily : 



