POLAR REGIONS. 



Polar ful microscope, when his conjectures were confirmed by 

 Heg1on. the discovery o!';min'-i!cu!es in immense numbers. The 

 *~~<~* m * larger proportion of these, consisting of a tr.m , 



substance of a lemon yellow colour, and globular limn, 

 appeared to possess very little power of motion ; but a 

 part, amounting perhaps to a fifth of the whole, were 

 in continual action. Some of these being seen advanc- 

 ing by a slightly waving motion, and others spinning 

 round with a considerable celerity, gave great interest 

 and liveliness to the examination. Hut the progresgive 

 motion of the most active, however distinct and rapid it 

 might appear under a high magnifying power, was in 

 reality extremely slow, for it did not exceed an inch 

 in three minutes. At this rate, they would require 151 

 days to travel a nautical mile. The condur, it is ge- 

 nerally believed, could fly round the globe at the equa- 

 tor, assisted by a favourable gale, in about a week ; 

 these animalcules in still water, could not accomplish 

 the same distance in less than 8935 years ! 



The vastness of their numbers, and their exceeding 

 minuteness, are circumstances discovered in the exami- 

 nation of these animalcules of uncommon interest. In 

 a drop of the sea water, examined by a power of 28.224 

 (magnified superficies,) there were fifty in number on 

 an average, in each square of the micrometer glass of 

 sloth of an inch in diameter; and as the drop occu- 

 pied a circle on a plate of glass containing 529 of these 

 squares, there must have been in this single drop of wa- 

 ter, taken from the surface of the sea, in a place by no 

 means the most discoloured, about 26,450 animalcules. 

 Hence, reckoning sixty drops to a dram, there would 

 be a number in a gallon of water, exceeding by one- 

 half the amount of the population of the whole globe ! 

 How insignificant, in point of numbers, is man ! What 

 a conception does it give us of the minuteness of cre- 

 ation, when we think of more than 26,000 animals liv- 

 ing, obtaining subsistence, and moving at their ease 

 without annoyance to one another, in a single drop of 

 water! The diameter of the largest of the animalcules 

 was only the two thousandth of an inch, and many only 

 a four thousandth. The army which Bonaparte led 

 into Russia in 1812, estimated at 500,000 men, would 

 have extended in a double row, or two men abreast, 

 with two feet three inches space for each pair of men, a 

 distance of 106^ English miles; the same number v of 

 these animalcules, arranged in a similar way in two 

 rows, but touching one another, would only reach five 

 feet two inches and a half! A whale requires a sea, an 

 ocean to sport in ; about a hundred and fifty millions 

 of these animalcules would have abundant room in a 

 tumbler of water !* 



In regard of temperature, the polar seas present some 

 remarkable facts. In situations where the sea is per- 

 petually covered with ice, and where the mean tem- 

 perature of the atmosphere is below 20, the tempera- 

 ture of the surface of the sea, it might be reasonably ex- 

 pected, would be about the freezing point in all sea- 

 sons. This is no doubt generally the case ; but there 

 are extraordinary exceptions, for in some situations of 

 this description, in the keenest frosts, and in the midst 

 of ice, the temperature of the sea, as high as the 76th 

 or 78th parallel, is sometimes 3 or 10 degrees above the 

 freezing point 



A circumstance equally extraordinary in the temper- 

 ature beneath the surface, was discovered by Mr. Scores- 

 by in the Spitzbergen sea. He found, by a series of 



experiments commenced in the year 1810, that in lati- 

 tude 1() J to 80", longitude 10 east to O'.IO' wet, in 

 situations where the surface temperature was about 2<j" 

 on descending fifty fathoms, it was often 3% and in 

 some instances 5 higher ; and in latitude SO 9 , at the 

 depth of 120 fathoms, the temperature was 36'.3, while 

 at the surface it was only 29.7. In one experiment, 

 at the depth of 4380 feet, the temperature was 37, and 

 in another, at the depth of 4566 feet, it was 38% the 

 temperature at the surface being 29" and 32. t 



In other parts of the globe the temperature is almost 

 invariably found to diminish on descending. Within the 

 tropics, in the Atlantic, the diminution of heat, on an 

 average of 39 observations by Dr. Horner, was J9M of 

 Fah. for 6'8 fathoms ; but in several instances the dif- 

 ference was upwards of 25. $ In the temperate zones, 

 the diminution of heat is less considerable, but still very 

 apparent ; and even in Baffin's Bay and Barrow's Strait, 

 so high as the 7 tth or 75th degree of latitude, a fall of 

 temperature was found to take place beneath the sur- 

 face. 



The depth of these seas corresponds, in a consider- 

 able degree, both in irregularity and quantity with the 

 height of the Arctic lands. Hence the commonly re- 

 ' ceived opinion, that where a coast is mountainous or 

 precipitous the sea which washes it is deep ; and that 

 where the land is low the sea is shallow, obtains a ge- 

 neral confirmation. There are many exceptions to the 

 law, indeed, but not a sufficient number to render the 

 general fact at all questionable. Thus between Spitz- 

 bergen and Greenland, where the coast on both sides is 

 high and mountainous, we find the sea at a distance 

 from land generally unfathomable. Mr. Scoresby 

 sounded in this sea several times with 4000, 5000, 

 6000, and in one instance with 7200 feet of line, with- 

 out finding bottom ; and in the comparatively narrow 

 sea of Baffin's Bay, Captain Ross found a depth of 1000, 

 1005, 1050, and 1070 fathoms, at the respective distan- 

 ces only of 6, 21, 24, and 9 miles from the land. In the 

 " Polar Sea," on the other hand, near the North Geor- 

 gian islands, where the land is generally low, Captain 

 Parry found the sea proportionally shallow. In the 

 sea on the north of Russia, where the prevailing cha- 

 racter of the land is low, the soundings are also shal- 

 low. 



The effect of the pressure of the sea at the great 

 depths to which some have sounded, is remarkable. 

 Mr. Scoresby made a number of experiments on the 

 comparative impregnation of blocks of various kinds of 

 wood, of different forms and magnitudes, by sinking 

 them to various depths from 2000 to 7000 feet. At the 

 depth of about 2000 feet, each kind of wood became 

 specifically heavier than water; and at the depth of 

 6348 feet, each kind was found to have gained from 

 106 to 161 grains per cubic inch in weight. The larg- 

 est pieces of wood gained the most in weight. A cube 

 of ash of four cubic inches solid content, gained 145 

 grains per cubic inch ; a cube of the same wood of half 

 the bulk, gained 137 grains; and cubes of an inch, at 

 different depths above 2000 feet, gained from 127 to 

 135 grains in weight. But these effects are not sur- 

 prising, when we consider the enormous pressure to 

 which the pieces of wood were subjected. The weight 

 of a column of sea-water 6348 feet high, without al- 

 lowing for the compression, being 2823 Ib. or 25 cwt 

 23lb. on one square inch of surface : hence the largest 



IV'ir 



i' v< n-. 



JWin. Phil. Jour*, iv. p. 111. t Account of Arctic Regions, i. 187. 



$ Dr. Homer's R0rk on the specific gravity of sea water, din. PMl. Jmr*. vi. 161. 



