

228 

since in whatever direction they move toward the centre 
there is the same deflecting force, either to the right or the 
left according to the hemisphere. 
The motion of the atmosphere being in a spiral toward 
and around the centre of the cyclone, the deflecting force 
depending upon the earth’s rotation, at right angles to the 
direction of motion, being resolved in the directions of 
the radius of gyration and tangent, the latter overcomes | 
the friction of gyration, and the former causes a pressure 
from the centre, decreasing the height of the strata of equal 
pressure in the cyclone, and consequently diminishing the 
barometric pressure. The barometric gradient of a 
cyclone is estimated in precisely the same way as in 
the case of the hemispheres, using for wv the lineal 
velocity of gyration obtained by resolving the real 
motion into the directions of the tangent of gyration 
and of the radius. It has been seen that a velocity 
of 30 miles per hour gives a barometric gradient of } of 
an inchin 350 miles on the parallel of 50. A gyratory 
velocity therefore of 100 miles per hour would give a baro- 
metric gradient of one inch of mercury in about 300 miles. | 
The velocities of gyration being known at all distances 
from the centre of motion, and consequently the baro- 
metric gradients, the difference of barometric pressure 
between the centre and the exterior, so far as it depends 
upon the gyratory motion, may be obtained by integra- 
tion. The effect of the centrifugal force of the gyrations 
is generally only a very small quantity of a second order, 
in comparison with the other, and the effect of it is 
entirely insensible, except in the case of small tornadoes, 
when the gyrations are very rapid close around the centre. 
In all the preceding estimates of the barometric gradient, 
it should be understood that the results belong merely to 
the force depending upon the earth’s rotation, and to this 
must be added the part belonging toa difference of density 
of the atmosphere, which in the case of cyclones increases 
the gradient, but diminishes it in the case of the 
hemisphere. For the general motions of each hemisphere 
form a cyclone, with the pole as a centre ; but having the 
denser instead of the rarer portion of the atmosphere at 
that centre. Hence the motions in any vertical plane 
through the centre are reversed, and it becomes what has 
been called an anti-cyclone, 
Cambridge, Mass. WM. FERREL 

RECENT MOA REMAINS IN NEW 
ZEALAND 
Il. 
HE Moa’s neck with the integuments attached, the 
discovery of which was announced in my com- 
munication dated April 3, has since then been forwarded 
to this Museum for examination by Dr. Thompson, and 
the following particulars may not be without interest to 
your readers. 
The total length ef the specimen is 16°5 inches, and 
includes the first dorsal and last six cervical vertebrz 
with the integuments and shriveiled tissues enveloping 
them on the left side. The surfaces of the bones on the 
right side, where not covered by the integuments, are free 
from all membranes and other tissues, but are quite 
perfect and in good preservation, without being in the 
least degree mineralised. 
The margin ot’ the fragment of skin is sharply defined 
along the dorsal edge, but elsewhere it is soft, easily 
pulverised, and passes into adipocere. 
The circumference cf the neck of the bird at the upper 
part of the specimen appears to have been about 18 
inches, and the thickness of the skin about ;%; of an inch. 
The only indication of the kind of matrix in which it 
had been imbedded was a fine micaceous sand, which 
covered every part of the specimen like dust, there being 
no clay or other adherent matrix. On removing this sand 
with a soft brush from the skin, it was discovered to be 
NATURE 



Rot 
5 ee 
Ete pee Bey 

folds, especially towards the upper part. 
some of which springs a slender transparent feather 
barrel, never longer than half an inch. On the dorsal 
surface a few of these quills still carry fragments of the 
webs, some being 2 inches in length. From these it 
appears that the colour of the feather barbs was chesnut- 
red, as in Apterix Australis, but that each barrel had two 
equal plumules to each quill, as in the Emu and Cassowary, 
andin this respect differed from the Apterix, the feathers of 
which have not even an accessary plumule. On the other 
hand the barbs of the webs of the feathers do not seem 
to be soft and downy towards the base as in the Emu. 
From the direction of the stumps of the feathers, it is 
evident that the portion of the neck which has been pre- 
served is that contained within the trunk of the body, and 
which, in the natural position, has a downward slope, the 
conical end of the specimen being where the upward sweep 
of the neck of the bird commenced, which accounts for 
the absence of the trachea with its hard bony rings, none 
of which are found among the soft parts which have been 
preserved. 
The integument was easily removed by dividing the few 
threads of dried, tissue by which it was attached. The 
shrivelled-up soft parts thus displayed could not be clearly 
distinguished, but may be grouped as follows :—-1. Astrong 
band of ligamentous tissue connecting the spinous pro- 
cesses. 2. Inter-vertebral muscles and ligaments. 3. A 
sheath diverging from the lower part as if to enclose the 
thorax. The only bone besides the vertebra was attached 
to this sheath by its tip, the other extremity being articu- 
lated to the first dorsal. 
Respecting the nature of the circumstances to which this 
remarkable specimen owes its preservation, I can only 
conjecture that the body of the bird must for a consider- 
able period have lain on its side in water or a swamp, and 
that the portion immersed was thoroughly macerated, 
while the exposed parts were desiccated and shrivelled up ; 
and that subsequently the whole remains were embedded 
in dry sand. 
As a fact of some interest connected with the history of 
the Moa, I should mention that in December last, Arch- 
deacon Williams informed me of the discovery of a series 
of enormous bird-foot marks on the surface of a layer of 
sand beneath a bed of alluvium at Poverty Bay. The 
| specimens he collected for me have unfortunately gone 
astray, but others have been placed in the Museums in 
Auckland and Napier, and I have just seen a pencil 
rubbing from the latter, taken by Mr. Cockburn Hood, 
which leaves no doubt that they are the footprints of a 
bird like the smaller-sized species of Dinornis, the largest 
| of these footprints being about eight inches in length. 
Janes HECTOR 
Colonial Museum, Wellington, New Zealand, May 15 
[We exceedingly regret that we are unable to repro 
| duce woodents of the beautiful illustrations by which Dr. 
Hector’s article is accompanicd.—-- EN. ] 


NOTES 
WE are glad to learn that our anticipations last week with 
reference to the Australian observations of the Total Solar Eclipse 
| of December next are being realised. The Royal Society of New 
of a dirty red-brown colour, and to form deep tranverse | 
South Wales is organising an expedition to Cape Sidmouth, a 
little south of Cape York. The President of the Royal Society 
of London has arranged that a few instruments of the newest 
construction shall be sent out from this country. 
Ir perhaps is not so generally known as it ought to be that 
the Emperor of Brazil, now in this country, is an enthusiastic 
astronomer, and has an appreciation of the value of science 
which places him in the highest rank among reigning sovereigns. 
During the last week he has visited the Royal and Mr. Huggins’s 
Observatory, and in a long interview with Mr. Lockyer has dis- 
cussed the bearings of the recent solar discoveries. 
[Fuly 20, 184 r 
The surface is 
roughened by elevated conical papillz, from the apex of — 


