60 
NATURE 
[Marcu 19, 1914 
The First Description of a Kangaroo. 
I HAVE just read in Nature of February 26 (p. 715) 
a letter by Mr. W. B. Alexander concerning the dis- 
covery of Australia and the first description of a 
kangaroo. It is stated there that the first discovery 
of this animal was made, not by-Sir. Joseph Banks 
on Captain Cook’s first voyage in 1770, but by Pelsart 
in 1629. May I be allowed to point out that a de- 
scription of a kangaroo is to be found at a much 
earlier date, viz., in the ‘‘Decades”’ of Peter Martyr, 
published shortly after 1500. Unfortunately this book 
is not accessible to me at present, so I must only 
point to numerous publications.of Mr. Edward A. 
Petherick, of the Federal Government Library, Mel- 
bourne, concerning the discovery -of Australia, who 
claims this honour for Amerigo Vespucci. According 
to Mr. Petherick, Peter Martyr states that in 1499 a 
southern coast was discovered (probably by Ves- 
pucci) in which trees grew of such magnitude that 
sixteen men standing around one could scarcely en- 
compass it (this would correspond to south-west Aus- 
tralia, between King George’s Sound and Cape Leeu- 
win). Amongst these big trees was found a monstrous 
beast, with the head of a fox, the hands of a man, 
the tail of a monkey, and that wonderful provision of 
nature, a bag in which to carry its young. The beast 
so described was caught alive with its young, but 
during the long voyage both died. The carcase of the 
dam was taken to the Court of Ferdinand and Isabella 
in the year 1500. This description is not as detailed 
as that by Pelsart; nevertheless it cannot easily be 
doubted that it refers to a kangaroo, which seems to 
have been known for the first time so far back as the 
end of the fifteenth century. 
The coast in question is supposed to have been dis- 
covered by Diego de Lepe, whose pilot was Vespucci. 
Tab. ESTREICHER. 
Laboratoire de Chimie IJ., Université de 
Fribourg (Suisse), March 3. 
The Movements of Floating Particles. 
WiLL any physicist be good enough to explain the 
following to an ignorant amateur? If a clean saucer 
be half-filled with a decoction of tea on the surface of 
which bubbles or unwetted shreds of ash (as from 
the consumed paper round the lighted end of a cigar- 
ette) are floating but not in a continuous layer, then 
if the decoction, after coming to rest, be gently. rocked 
the floating particles will partake of its perpendicular, 
but little, if at all; of its lateral motion. Sunken par- 
ticles, on the other hand, will partake of the lateral 
motion. Again, if the saucer be gently tilted the 
fluid will flow away, but each floating particle will 
remain stationary, and will be deposited under its 
original position. 
Why do not the particles partake of the lateral 
motion? Does the surface of the decoction form an 
incompressible, but flexible, film, which (in the saucer) 
may be added to but not subtracted from, under which 
the rest of the fluid slides with little friction. And when 
the fluid flows away does this film remain behind to 
form that portion of the fluid that wets: the saucer? 
Or do solid, but invisible, particles come up and form 
a continuous sheet on the surface? Against the latter 
supposition is the fact that particles dropped on the 
advancing edge of the decoction remain stationary. 
Particles floating on the surface of ordinary tap water 
move with it much more freely; water in which table 
salt has been dissolved behaves like tap water. But 
even in sea water we see froth left. behind by receding 
ripples. G. ARCHDALL REID. 
‘“Netherby,’’ 9 Victoria Road South, Southsea. 
March 3:3. 
NO. 2316, 1VOr1 O23) 
KINEMATOGRAPHY AND ITS 
TIONS. 
R. TALBOT is to be congratulated on having 
produced a book which must appeal 
strongly to the interest of the general reader, 
even though he may. have no intention whatever 
of becoming a “kinematographer.’’ A word here 
on this terrible term. It may be correctly derived 
_APPLICA- 
| from the Greek, while it certainly admits of many 
pronunciations, variously wrong, but the frequent 
collision with these six syllables when otherwise 
interested must impress upon the reader of Mr, 
Talbot’s book the desirability of finding some new 
word of one syllable, not derived anyhow,. such, 
for instance, as the mechanic and the electrician 
have found in the words crank and boost, so that 
; neither attention may be arrested nor printing ink 
and paper wasted. PNR 
The main purpose of the book is to show what 
has been done in. many different fields and the 
nature and cost of the apparatus which an amateur 
would be likely to use, rather than to give instruc- 
tion. in the details of the art. . Incidentally, the 
commercial value of lucky-chance films of. the 
' amateur is pointed out, but it is not very clear 
what the cost of the unlucky-chance miles of: film 
that will be worth nothing is likely to be. 
On first opening the book the reader will see a 
picture of a fine cow which appears to have 
suffered at the hands of the cattle-maiming gang. 
Closer inspection will show that the injury is a 
door in the side of the beast, which, according to 
the legend below, is 15 ft. high. It was made by 
Messrs. Newman of papier-mdché, so that the 
operator might get inside with his camera with ~ 
the intention of taking lions and other beasts 
unawares. Passing on from this testimonial to 
the credulity of the savage beast, we find numer- 
ous full-page or half-page enlargements of single 
pictures taken from the strip, so perfect in focus 
and detail that it is scarcely possible to believe 
that it has all been derived from a miniature 
1x2 in.. only in -size.. A-reference ‘to some of 
these only. will indicate the great variety of 
subject which is open to those who practise this 
new art. There are lions at lunch in the jungle, 
a polar bear diving in the arctic sea, birds feeding 
their young, a vulture preparing to fly, and taken 
at such close quarters that every feather is clearly 
defined, eighteen successive photographs taken 
during a single beat of a pigeon’s wing, and 
fifteen of the opening of a convolvulus, both from 
_the Marey Institute, two X-ray films from the 
same institute by M. Cavallo, one of sixty pic- 
tures showing digestion in the intestine of a frog, 
and thirty of the movements of the gizzard in a 
fowl, and others from the same quarter. 
Then by the aid of the microscope and the 
“ultra-microscope,” smaller forms of life may be 
seen in motion. For instance, there is the head 
of a spiny monster which is nothing more than a 
blue-bottle eating honey from off a needle, and 
there might have been, but are not, illustrations 
By Frederick A. 
1 ** Practical Kinematography and its Applications.” : 
i Price 
Talbot. Pp. xii+262+plates (London: W. Heinemann, 1913.) 
3s. 6d. net. 
