82 
POPULAE SCIEI^OE NEWS. 
[June, 1891. 
some good reason generally appears for their 
absence from the solar spectrum. Of course there 
is but little evidence of tlieir absence from the 
sun itself; were the whole earth heated to tlie 
temperature of the sun, its spectrum would pro- 
bably resemble that of the sun very closely." 
The powerful instrument used at Baltimore for 
photographing spectra, and the measuring engine 
constructed to fit the photographs so that its 
readings give the wave lengths of lines directly 
within 1-100 of a division on Angstrom's scale, 
give the foregoing results a weight superior to 
many others published. 
— ♦♦( 
CHISELLING GUN COTTON. 
Gun cotton, said Professor Munroe, in begin- 
ning his lecture on that explosive, at the Lowell 
Institute, recently, is pure cotton dipped in a 
mixture of pure nitric and sulphuric acids. In 
seeking a method by which these ingredients 
might be obtained absolutely pure and the cotton 
thoroughly treated with the acids, many years 
have been spent and serious accidents have oc- 
curred. 
According to the Boston Journal of Commerce, 
the lecturer traced the experiments with the ex- 
plosive from its discovery, in 1832, up to the pres- 
ent time, and spoke of several of the most fatal 
explosions which attended the experimental stage. 
After experiments by Professor Hill, of the United 
States torpedo station, gun cotton was adopted as 
an explosive for use in the navy in 1884. In pre- 
paring it for this service the gun cotton is, l)y 
successive pressings in hydraulic presses, the last 
of which has a pressure of 6,800 pounds to the 
square inch, made into little blocks measuring 
iYi inches each way. It now contains from 10 to 
16 per cent, of water, but when Issued to the ser- 
vice contains 35 per cent. Before being made up 
into blocks it is carefully tested. 
Professor Munroe declared that gun cotton, cor- 
rectly prepared and handled according to direc- 
tions, was the safest of the explosives to use. It 
was dangerous only when the materials had not 
t)cen thoroughly purified, or the union of acid and 
cotton incomplete. In proof of what could be 
done with it, a picture was thrown upon the 
screen showing tlie workman cutting it with 
chisel, jig saw, and lathe to fit it into a shell. 
Another illustration was the extinguishing of a 
block that was burning by pouring water upon 
it. Two thousand pounds of it had been burned 
in a bonfire without an explosion. 
One volume of the explosive gives 829 of the 
gas, and the pressure developed by combustion is 
eighty-one tons to the square inch, and by detona- 
tion 157.5 tons, the latter being in contact, how- 
ever. The eftect of the explosion of one particle 
on another is so rapid that it would take only one 
second for it to pass through 19,000 feet of the 
explosive. 
It was shown by the stereopticon that the let- 
ters U. S. N., with the date of manufacture, that 
are on the bottom of each block, are impressed 
upon an iron plate upon which the gun cotton 
may be exploded. It is a curious fact that, if the 
marks on the block are in relief, the reproduction 
on the iron will be raised, and, if cut in, there will 
be an indentation on the plate. Professor Mun- 
roe's theory is that when the letters are cut into 
the explosive, the gases generated in the indenta- 
tions are hurled from them as a projectile from a 
gun. If a leaf or a delicate piece of lace be laid 
between the gun cotton and the iron, its impress 
will be left in all the perfection of outline of the 
original, though the article itself is absolutely 
annihilated. 
ALLOTROPIC FORMS OF METALS. 
In connection with Mr. Carey Lea's remarkable 
discoveries of the allotropic forms of silver, the 
different forms of other metals, as described by 
Mr. W. C. Roberts-Austen in the Engineer, are 
worthy of notice. He remarks that the impor- 
tance of the isomeric and allotropic states has 
been much neglected in the case of metals. Joule 
and Lyon Playfair showed, in 1846, that metals in 
different allotropic states possess difl'erent atomic 
volumes ; and Matthiessen, in 1860, was led to the 
view that in certain cases where metals are al- 
loyed they pass into allotropic states, probably 
the most important generalization which has yet 
been made in connection with the molecular con- 
stitution of alloys. Instances of allotropy in pure 
metals are : Bolley's lead, which oxidizes readily 
in air; Schutzenberger's copper; Fritsche's tin, 
which falls to powder when exposed to excep- 
tionally cold weather ; Gore's antimony ; Graham's 
palladium and allotropic nickel. Joule has also 
proved that, when iron is released from its amal- 
gam by distilling away the meicury, the metallic 
iron takes fire on exposure to the air, and is there- 
fore clearly different from ordinary iron. 
[Practical Confectioner.] 
SELECTED EECIPES. 
Orange Puffs. — Grate the rind of four oranges, 
add two pounds of sifted sugar, pound together, 
and make it into a stiff' paste with butter and the 
juice of the oranges ; roll it and cut it into shapes, 
and bake in a cool oven. Serve piled upon a dish, 
with sifted sugar over. 
Onions a la Don Carlos. — Take a Spanish 
onion and cut a thick slice from the root end, and 
place it in boiling water and parboil it; then 
throw it into (fold water, dry it, scoop out the 
inside, and fill it with a mixture of pork sausage 
meat and mashed potatoes in equal parts, mixed 
together with the yolk of an egg. Have ready a 
small piece of boiled ham and place under the 
onions, add a good brown gravy, stir them 
quickly, and serve hot. 
Shrimp Cutlets. — Wash and pick a pint of 
shrimps, and chop them with a silver knife. Put 
on half a pint of milk to boil. Rub together a 
large tablespoonf ul of butter, three ditto of flour, 
stir till the boiling milk forms a thick paste, add 
the yolks of two eggs ; cook a moment, take from 
the fire, add the shrimps, a little salt and cayenne, 
and ten drops of onion juice; stand away to cool. 
When cold, form into cutlets, dip in egg and 
bread crumbs, and iry. Serve with cream sauce. 
Tomato Lyonnaise. — Peel and cut into small 
pieces half a dozen good-sized tomatoes. Slice 
four onions. Fry the latter in a pan with butter 
until they begin to change color, stirring fre- 
quently to prevent scorching. When they become 
yellowish, pour on the tomatoes, juice and all, 
season with salt and pepper, and cook for twenty 
minutes, keeping them well stirred. Add a cup- 
ful of good gravy and a tablespoonful of minced 
parsley, and simmer for five minutes more. If 
too thin, thicken with a little flour wetted with 
cold gravy. 
NouKLA Pudding. — Take two ounces of butter 
and mix in one and a half ounces of flour; put 
them into a stew-pan and mix till smooth, add 
half a pint of milk, and cook over the fire till it 
becomes thickish; remove from the fire and mix 
in two ounces of grated Parmesan ; then add two 
eggs, working them in one at the time, and 'some 
salt. Put a stew-pan on the fire with one quart 
of milk; boil it up and put in the above mixture 
in lumps the size of a cob-nut ; put these noukles 
at the bottom of a tart dish, and cover with a pint 
and a half of Parmesan sauce, using the milk in 
which the noukles were poached. The sauce must 
not be too thick. Put in the oven and bake grad- 
ually for half an hour. 
Princess Potatoes. — Boil the potatoes and 
steam them dry as possible ; pass them through a 
wire sieve, and mix with them one and a half 
ounces of butter, a yolk and a half of eggs, one 
ounce of grated Parmesan cheese, a pinch of salt, 
and a little cayenne pepper. These ingredients 
must be added to each pound of potatoes. Mix 
all. together, and when cold roll the mixtnre into 
little rolls, using a little flour while doing so to 
prevent the mixture sticking. The rolls should 
be an inch and a half long and an inch in diam- 
eter. Now place them on buttered baking tins, 
brush them over with a whole beaten-up egg, and 
bake them until they are of a nice pale color. 
When dished up, pour a little warm butter over 
them, and sprinkle them with finely-chopped dried 
parsley. 
^*^ 
LABORATORY NOTES. 
To Deodorize Bottles that have contained 
benzin, benzene, thymol, naphthol, and other sim- 
ilar strong-smelling substances, a simple and ef- 
fectual plan is to pour into each a small portion 
of a mixture of sulphuric and nitric acids, and 
allow it to flow over all parts of the interior. 
After it has been left for about an hour in the 
bottles, which are occasionally taken up and 
turned about so that all parts Of the internal sur- 
face are attacked by the acid, it will be found 
that a good rinsing with plain water will leave 
them as good as new. 
A Substitute for Starch-Paper.— A wi-iter 
in the Chemical News says : " While analyzing 
qualitatively a mixture containing iodides and 
bromides the other day, it occurred to me, as my 
starched paper was gone, and I was disinclined to 
"break oft' my work to make more, that I might 
find an efficient substitute in ordinary white writ- 
ing-paper. I tried this after moistening with 
water, and found to my delight that it did as well 
as the best starch-paper that ever was prepared ; 
and why not, seeing that in the process of manu- 
facture, writing-paper — or, indeed, any common 
paper — is finished with size which contains a 
notable quantity of starch?" 
Label Varnish. — Among the numerous form- 
ula; for this article, the following is deserving of 
a high place : Reduce 6 parts of African copal to 
fine powder, and mix with it an equal weight of 
powdered glass; place the mixture in a bottle 
capable of holding 50 parts, and add 1% parts ol 
camphor and 25 parts of ether. Allow to digest 
during a month with occasional agitation. Tlien 
add 6 parts of absolute alcohol, shake well, and 
set aside for a fortnight ; pour off" the clear super- 
natant varnish for use. Paper to which this 
preparation is to be applied should be first coated 
with a solution of isinglass in a mixture of spirit 
and water (1 : 3, respectively). 
An Improved Meltinc^point Apparatus has 
been devised, consisting of a two-necked bottle 
containing mercury, which can be heated in an 
air-bath. Tlirough one of the openings a ther- 
mometer passes, and also a wire from a voltaic 
cell. Through the other passes the drawn-out 
end of a glass funnel. The substance to be ex- 
perimented upon is placed in this funnel in the 
fused state, and allowed to solidify. The space 
above it is then filled with mercury and the fun- 
nel is introduced in the bottle. The second wire 
