914 Transactions.—Miscellaneous. 
area of ocean in the latter hemisphere, not only are there fewer local 
disturbing eauses in the shape of spacious continents and lofty mountains, 
but also the observatory sites are proportionately fewer. Hence the Southern 
isobars are in many cases merely arbitrary and approximate lines drawn 
from one point, at which continuous trustworthy observations have been 
taken, to another similar point perhaps 5,000 or 10,000 miles away, as from 
the Cape of Good Hope to New Zealand, the intermediate points being 
furnished by casual intermittent observations made by passing vessels. 
It is possible that permanent observations, could they be established in as 
many situations as in the Northern Hemisphere, might necessitate consider- ` 
able alterations in the isobars at present accepted. However, taking the 
existing isobars as a standard, we find that whereas the isobar of 80 inches 
follows a mean latitude of about 42° in the North Atlantie Ocean, the 
latitude of the same isobar in the South Pacific is only about 85° 
Similarly, the isobar of 29? 70 inches is found at a mean latitude of about 
60° north, and only 48? south. The very low pressure prevalent in 
the vicinity of Cape Horn is a meteorologieal feature well known to 
navigators. 
8. All this of course only goes to prove that the mean pressure is less in 
the Southern than in the Northern Hemisphere. Such in fact might have 
the form of Dr. Newman's minor premiss, and so stated undoubtedly it would 
have been irrefragable, but in that case, as the middle term of the syllogism 
would have been undistributed (it not being shown that the rule included 
New Zealand as compared with Great Britain), the argument must have 
fallen to the ground. The real question is—not whether the pressure in 
New Zealand be less than in the corresponding northern latitudes, but 
whether it be less than that of England, from whence, to use Dr. Newman’s 
words, the English race is transplanted. 
9. Dr. Hahn, of Vienna, in his Essay on the Climate of New 
Zealand,* says: “ It is a well-known fact that the pressure of air decreases 
very rapidly towards the Pole in the Southern Hemisphere. We find this 
confirmed in New Zealand, where the medium pressure of air at the level 
of the sea, between 87° and 46° 8. latitude, decreases from 29-981 inches to 
99-804 inches; whereas in the Northern Hemisphere in these latitudes the 
pressure of air remains between 80:009 and 80-001 inches." 
10. Dr. Hahn is not quite aceurate here. Reference to the isobaric 
chart will show that the isobar of 80 inches, which in the Southern Hemis- 
phere lies entirely between latitude 32° in the South Atlantic Ocean, and 40° 
in the Indian Ocean, in the Northern Hemisphere varies most remarkably, 
*Meterological Report, N.Z., 1873, Hector, p. 77. 
