382 
vation of the Bhell fof which faoilities well be provided 
iu the Bill draf ted for Pnrliament. 
Tills will, we understand, be Mr. SavilJe-Kcnt's latt 
ofi&cial visit to Thursday Islaud in (onneetion with 
his present eugagemonfc by the QuoeusUnd Govern- 
ment, Mr. Kent, has received an invitation from the 
West Australian Goveroment to report and advise upon 
the pearl shell and other fishe) ies of that colony 
on the termination of his engagement here. He has 
however decided to return to England first for at 
least a year or two, for the purpose of supervising 
the publication of one or more comprehensive works 
on the fish and fisheries cf Queensland. — Torres Straits 
Pilot. Aug 29tb. 
[The above refers, of couree, to the large mother, 
of-pearl shells, but has a close bearing on the 
treatment of our small pearl oysters, for culture 
and pearl formation,— Ed. T. A.] 
-® 
ECHOES OF SCIENCE. 
Captive balloons ser-m to be pfculiarly liab!e to be 
struck by lightning. Within the last six or seven 
year.^ no f'-wer than thrre have been destroyed in this 
way, and the total number cf them cannot be great. 
There was one struck at Turin, another at Barcelona, 
and, lastly, one at Chicago. Two of these, including 
that of Chicago, were struck when moored near the 
ground. Of course, a captive balloon in connection 
with the earth resembles the kite cf Franklin, and 
is liable to "draw" the discharge, but the fact that 
it contains hydrogen, which is a far better conductor 
of electricty than air, may have something ta do 
with the matter. The siik bi\a with hydrogen may 
be compared to a mass of metal enclosed in a 
thin layer of irsulator. "When, as hiippens in ill- 
made balloons, the gas escapes through the pores, 
the liehtning is tempted in that direction. G-iffard's 
impermeable balloons have not as yet been struck. 
It may be added that aeronauts, rememberint; the 
conduolivity of hydrogen, should avoid opening tbe 
valves of their balloons while passing below a thunder 
cloud, in ca.se they should precipitate the discharge. 
It is well known that the valley of the Orinoco 
is connected to that of the Eio Negro by the 
Cassiqniares river, and it is here that a parly 
of explorers have recently discovered immense 
forests of tbe india-rubber trees, as well as other 
trees very like, it not indenlical, with the gut'aporcha 
trees of tbe Malay Archipelago. As the latter 
are all but extinct now, the news is nil the more 
important . — Globe. 
NOTES OF POPULAB SCIENCE. 
By Dii. J. E. Taylor, p.l.s., f.g.s., &c., 
Editoe of " Science Gossip." 
Two French mineralogists, Messrs Fouque and 
Levy, have produced micaceous trachyte by artificial 
means, The trach\te was obtained by the artificial 
action of water under pres=ure on a glass resulting 
from granite, and at a bright-r. d heat. The rock 
was homogeneous, and in its sections exhibited beauii- 
ful oct'.hedral crystals of a variety of sp'ral, in 
connection with orthoclase and black mica. 
An important paper was read before tbo Geo'ogical 
Society recently by Mr. J. J, Lister, on the geology 
of the Tonga Islands. Many are purely volcanic in 
Btrucluro, but there arc .^ome j)ossessiiig undoubted 
ttratified limef-tone.s crowiled with marine sbellc, 
ehowing evidences of elevation from con&iderat.le 
depths of the sea. Mr. Lisier also discovered genuine 
I'lutonio rocks on tbe islandn. The paper has an 
important bearing on the origin of coral reefs. 
There is perhapn, not a moro useful natural order 
of plants in tlie world than the cruciferai — our inus'ards, 
er<ss(;', tnrnips, radishes, &c. All are remarkahlo for 
their pungency, and etjually fo for the localisation 
of this quality. Soinotimos it is situated in one part 
aometiracH in another. Moreover, it has long been 
recognised aa largely due to Bulphur, and anybody 
who has had to do with the waste products of 
cruciferous plants, from cabbage water to rotten turnips, 
is well awure tbey freely give off a large quantity of 
sulphuretted bycirogen gas. A French agricultural 
cheaiiwt has just shown that the composilion of the 
various active principles of the cruciferaj varies from 
species to species. Black mustard contains tinigrin, 
be ides the ferment myrosin. Tbe horse-radish docs 
the Fame. White mustard contains sinalbiu iu placo 
of sinigrin. The active ptiueiple of watercress is 
sulpbocyaiiate of batAric alcohol. The roots, stems, 
leaves, &c., of other common cruciferous plants contain 
a mixture of sulphur and .sulphooyai ate of allyl. M. 
Guignard coacludes that nearly all cruciferous plants 
are ijrovided with special cells ■which contain a 
particular ferment known as rayro = in; and that it 
is in the cells of their seeds this occurs most abun- 
dantly. 
The methods by which plants obtain their nitrogen 
are always fruitful subjects cf discussion and interest 
to botanists. Two German natural .s's have recently 
published tbe results ot fonie peculiar experiments, 
chiefly cu the leaves of leguminous plants. They fi.nd 
that green lea'.'es contain more nitrogen in tbe even- 
ing than on the following morciug, and this appears 
to depend on the quantity of asparagin being larger. 
The reason given is that Bspaoagin and sugar are 
the best nutriants for the fungus which lives sym- 
biotically on the roots of most legumioous plants. 
The largest proportion of nitrogen pressnt in the 
evening was in three common leguminous plants — 
T. ifoliuni pratense (or common clover), Medicago 
sativa (eominon medick), ui:d Lathyrus sylvestris. 
The same fact was noticed in connection with herbage 
plants belonging to other na'ural orders. The moral 
of (his discovery eeems to be thit we ought to cut 
our hay at niejht, and not begin in tbe morning as 
is usually the case, if we wish it to contain the 
greatest quantity of nitrogen or feeding stuff. 
Mr. Carus- Wilson i as for tome years past been 
studying the phenomena of "musical sand," or sand 
grains whose movements give out musical sounds. He 
writes in tbe Cliemical Nttus \o say he has succeeded 
in producing musical notes from sand which was 
never before mutica', and that he has obtained 
similar results from the mute or "killed" musical 
sands which have been temporarily deprived of their 
musical properties. P^ofe^sor Crookes adds a note 
to Mr. Wilson's communication, staging he had wit- 
nessed that gentleman's experiments with musical 
sands, sands originally musicnl, musical .'■ands which 
had been killed and then revived, and san'ls ori- 
ginally mute which had bad the gift of music con- 
ferred upoT them. Mr. Wilson w'ill shortly explain 
these interesting phenomena in detail. — Austral 'sian. 
THE GREATEST BUTTER COW OF . 
THE WORLD. 
In our last September issue we gave an illustration 
of the celebrate d Jersey cow " Buro'.isauia, " de-cri- 
bing her as the greatest bnttf r cow of the world, she 
having produced the up till that time, uuhe.Trd of 
amount of 945 pound?, i) i ui ces of good merchantable 
butter within the year. . We little thought, then, that 
within six months we shoul 1 have to depose her from 
the p'Dnacle of fame, an^l lank her only second in tbe 
list, and ytt such is oar positio:! <o-day. The Holstein- 
Frieaian cow " Pauline Paul," owned bj' J. B. Dutcher 
& Sou, of Pauling, New York, has just compltted a 
test of 36.5 (lays tor hutter pr- ductiou, and has made 
within that time tbe unparalleled record of 1,163 pounds, 
15^ ounces ol! marketable butter, well washed, aud 
salted at the rate of one ounce to the pound. We 
have not the details of the food consumed, beyond the 
fact that she was fed a ration composed of three parts 
bran, two parts ground oats, and one part corn me a', 
by msasure. Of this mixture, she wes fed per day not 
exceeding twenty-seven pounds, to wbieU was added 
throo pounds of cotton seed. Slie had neither slop nor 
