10 
POPULAR SCIENCE NEWS. 
[January, 1891. 
fulminlc acid, (from fulmen, the thunderbolt). 
The free acid has never been produced, but the 
fulminate of mercury is easily and cheaply pre- 
pared, and has the empirical formula Hg C2 X2 02. 
Like nearly <all the compounds of nitrogen, the 
molecule is extreraelj- unstable, and a slight blow, 
a temperature of 363° F., or even contact with 
strong sulphuric or nitric acid, causes the mole- 
cule to break up like a house of cards, and to be 
transformed into nitrogen and carbonic oxide gases 
and vapor of mercurj-. Like nitro-glycerine and 
other high explosives, tlie reaction, or explosion, 
takes place in the molecule itself, and is not, as in 
the case of gunpowder, simply a very rapid com- 
bustion, and this property explains the intense 
force of the explosion. It is estimated that at the 
moment of explosion a pressure of 720,000 pounds 
to the square incli is generated. 
Mercuric fulminate is prepared by dissolving 
mercury in an excess of nitric acid, and adding 
alcohol ; a very brisk reaction and eflfervescence 
soon begins, and the fulminate separates as a 
crystalline precipitate. The actual chem- 
ical clianges wliicli take place in this re- 
action are very complicated, and are not 
thoroughly understood, but the final re- 
sult is as above stated. As soon as red 
fumes begin to appear, water is poured 
in to stop the reaction, and the precipitati; 
collected on a filter, washed, and kept 
moist until needed for use. This experi- 
ment is a very dangerous one for inexpe- 
rienced persons, both from the risk of 
explosion and tlie poisonous gases evolved, 
and should not be attempted by beginners 
in chemistry. 
Large quantities of this fulminate are 
manufactured at Prescott, in Ontario. 
Two or three times a year an American 
fb'm sends a party of workmen to this 
place with the necessary quantity of nitric 
acid, mercury, alcohol, etc., and for a 
few days the town is redolent with the 
fumes of alcohol, aldehyde, ethers, etc., 
until the desired amount of the explosive 
is prepared and safely packed in kegs of 
water for transportation to market. The 
profits are said to be very large, but we 
hardly think any one will grudge the 
manufacturers of this treacherous com- 
pound all that tliey can make out of it, 
or would desire to undertake the work 
themselves at any price. With proper 
care the risk of an accident is small, but 
when an explosion does occur the destruc- 
tion is complete and there is little or no chance 
for escape. 
The pure fulminate is so powerful that, in the 
manufacture of percussion caps, it is generally 
mixed with other substances to moderate the price 
of the explosives. Chlorate and nitrate of potash, 
sulphide of antimony, and powdered glass have 
been used for tliis purpose ; but it is probable that 
they have no chemical effect upon the explosive 
decomposition, but simply act mechanically by 
diluting the pure fulminate. One pound of mer- 
cury will produce enough fulminate to fill over 
25,000 percussion caps. 
One of the most interesting applications of ful- 
minate of mercury is its property of detonating 
dynamite and other nitro-glycerine explosives. 
Dynamite cannot be easil}' exploded by contact 
with flame, and it may even take fire and burn up 
quietly, but if a tube containing fulminate ofmer- 
cury be placed in the midst of a charge of dyna- 
mite and exploded in the usual way, it induces a 
similar explosion or detonation of the whole mass 
of dynamite with its well-known powerful effects. 
It seems as if tlie violent detonation or rapid 
molecular vibration of the fidminate induced a 
similar detonatory vibration in the molecules of the 
dynamite, just as the strings of a piano are set 
into musical \'ibration when a note of the same 
pitch is sounded in their vicinity. 
Fulminate of silver is analogous in composition 
to that of mercury and is made in a similar way, 
but is much more violently explosive. It detonates 
when merely pressed with a hard body, and at a 
temperature a little above that of boiling water. 
Even when wet it is not safe to keep it in a glass 
bottle, and we know of a case where a quantity 
exploded while being washed on a filter, the prob- 
able cause being tlie friction of the stream of 
water which was being poured over it. The glass 
funnel was shattered into atoms, but the chemist 
who was washing it escaped, almost miraculously, 
without serious injury. A compound silver-am- 
monium fulminate is also known, which is even 
cal affinity of the nitrogen, and when this is over- 
come by percussion, heat, or a stronger cliemical 
affinity, tlie whole molecule collapses, as it 
were, with explosive violence, and is instantly 
changed into simpler and more stable chemical 
substances. 
A, The Double Coconut Palui, (after Kerchove). B, The 
Fruit Shell, cut in half, the husk ami contents heing 
removed, (after Drude). 
more violently explosive than the silver salt. 
Fulminates of zinc, copper, sodium, potassium, 
etc., are known and are all exjilosive, but have 
only a theoretical interest. Xiti'ogenous com- 
pounds of silver and gold are also known to chem- 
ists by the names of fulminating silver or gold, 
but they have" no connection with the true luhni- 
dates, and are of little consequence. 
The effect of the element nitrogen upon its com- 
pounds is one of peculiar interest. The element 
itself is a neutral, inactive body, with no partic- 
ular characteristics and of little practical conse- 
quence, but when in coml)ination with other ele- 
ments it usually confers an element of instability 
upon the whole compound, like an arch with a 
defective keystone. If this falls, the whole arch 
is destroyed, and so in the molecules of the fulmi- 
nates and shiiilar bodies ; the integrity of the 
molecule seems to depend upon the feeble clieml- 
[Original in POPCLAR SCIENCE News.] 
A GIOANTTC FRUIT. 
BY FRED'K LEROY SARGENT. 
Several centuries ago, before the Indian Ocean 
had been well explored, the curiosity of those who 
sailed its waters was often much excited by the 
appearance of something like a huge double coco- 
nut, of forty pounds weight, floating on the sur- 
face. Similar fruit was found occasionally washed 
up on the sliores of Ceylon and the adjacent coast ; 
but no one had ever seen a tree thus fruited, and 
so some fabulous submarine plant was believed to 
produce them. The fruit was called coco de mer, 
or "sea coconut,'" and many were the marvellous 
tales which arose to account for its origin. More- 
over, as has so often been the case with 
other natural objects of mysterious origin, 
most extraordinary curative powers were 
ascribed to this wonder of the sea. Thus 
a medicine prepared from the kernel was 
supposed to possess great potency, and it 
was believed that water drunk from m>- 
sels made out of the shell was a pre- 
ventive against all disease. Consequently 
the nuts were treasured almost religiously 
in India, and brought extravagant prices. 
The first real knowledge of where these 
mysterious nuts came from was obtained 
in the year 1742, by French navigators, 
who discovered the Sechelles group of 
islands, and on two of these found large 
numbers of a species of palm bearing the 
famous "double coconuts.'" "The aston- 
ishment of those previously acquainted 
with the coco cU mer," writes one who has 
visited tlii-se islands, "may well be im- 
agined, upon their finding large forests 
entirely composed of this palm, growing 
upon a small and quite uninhabited island, 
and towering far above all ordinary tropi- 
cal vegetation."' It is not a little remark- 
able that the species, so far as known, 
grows only on the small islands where it 
was first seen, and the plant has been 
named accordingly Lodoicea SecheUarum. 
Since the time of its discovery much 
curious information has been gathered 
regarding the parent plant vhieh pro- 
duces this largest known of all tree fruits. 
Especially noteworthy is the long period which 
the plant takes to prepare itself for the great 
work of fruit-making. It must vegetate thirty 
years before a flower-bud is produced. During 
this time it builds a columnar trunk, which, 
since it must support the heavy fruit and 
resist the force of tropical gales, needs to be of 
extraordinary strength. To compensate in a 
measure for the consequent rigidity, a nnitiuc 
arrangement acting like a ball and socket joint is 
developed at the base. Tlio lower end of the 
trunk is hemispherical and fits into a sort of bowl 
composed of extremely hard material like the 
shell of the nut, and pierced by holes the size of a 
thimble, through which the roots make their way 
into the surrounding soil. This arrangement per- 
mits the tree to sway in response to strong winds 
in spite of the rigidity of the trunk. The maxi- 
mum height of the tree, about one hundred feet, is 
attained in about as many years. This statement 
