THE TOUNG SCIENTIST. 
11 
them with kerosene to save his fruit. They finally 
gathered on the warm side of a brick building, 
spinning thousands of cocoons. It would seem 
from this that the Californians are likely to have an 
acclimated silk- worm, if nothing more. 
liiterature vs. Gymnastics, — A Michigan far- 
mer puts it rather suggestively when he writes to 
the faculty at Yale College : " What are your 
t{ rms for a year ? And does it cost anything extra, 
if my son wants to learn to read and write as well 
as to row a boat.?" 
Nothing but Leaves._We find in our English 
exchanges a number of inquiries in regard to the 
drying and coloring of leaves for ornamental pur- 
poses. If an interest should be awakened in this 
subject, the collecting and exporting of autumn 
leaves from this country will undoubtedly become 
a matter of importance. The gorgeous colors of 
our forest leaves are universally allowed to be un- 
rivaled. 
Liong-Iiived Errors—The assertion that plants 
take up whole diatoms and assimilate them, an 
assertion which was made primarily for the purpose 
of aiding the sale for manure of the enormous 
Eichmond deposits of fossil infusoria, was thor- 
oughly refuted in the "American Journal of Micro- 
scopy," and the refutation was extensively copied 
into other papers. And yet one of our most popu- 
lar scientific weeklies reiterates this stupid blunder 
in a recent issue I 
Iron Bird Siiot. — It has recently been suggested 
that iron shot would be better for sporting pur- 
poses than \ey.d, and the originator of the idea has 
elaborated complicated machinery for making the 
article. His reasons for preferring iron to lead are 
that shot made of the former metal would keep its 
shape better, not being liable to get bruised and 
flattened, either in the pouch or the gun. He does 
not seem to know that small iron shot would be 
almost worthless as compared with lead, owing to 
its lightness. Substitute iron shot for leaden pel- 
lets, and you will reduce the range of your gun 
nearly one-half. 
Non-Condnctor for Higli Temperatures. 
Mr. Fletcher, of Warrington, England, produces a 
very perfect non-conductor by mixing one part of 
ganister or refractory clay and six of sawdust, 
ramming them in a mould and firing. This makes, 
after burning, a firm cellular mass, in texture 
almost like pumice stone, and its power of retain- 
ing heat is such that, in this casing, which is only 
half an inch thick, half a pound of cast iron may 
be melted, and the furnace, crucible and all, may 
then be held in the hand without feeling the heat 
to any considerable extent. The applications of 
this material are numerous and important. As a 
jacket for ordinary furnace work, it will prove in- 
valuable in all places except when exposed to 
mechanical wear. We would suggest that where it 
is liable to be abraded, a coating of some firmer 
material be applied. This latter will no doubt con- 
duct heat better, but if protected in this respect by 
a layer of the new non-conducting material, the 
loss will be trifling. 
The Paris Exhibition — The buildings of the 
coming Paris Exhibition in 1878 are the largest yet 
conceived for the purpose. The nave of the main 
building is nearly 2,200 feet long; the viata, which 
includes the two vestibules, is more than 2,360 feet; 
and each of the transepts and vestibules, more 
than 1,100 feet. The eight industrial courts are all 
parallel, and are divided into two series of four 
each, one series being devoted to thje productions 
of France, and the other to the rest of the exhibit- 
ing nations. In the centre of the garden between 
the two series are two ranges of fine art galleries. 
On the opposite side of the river is the Trocaden 
Palace, which is to be devoted to the history of 
man from the savage state down to the most mod- 
ern appliances of science and art. It will afterward 
be used as a municipal museum. 
Plaster of Paris— A writer in the "English 
Mechanic," having occasion to prescribe plaster of 
Paris as an ingredient for a cement, calls attention 
to the fact that common plaster, as usually sold in 
the oil shops, will not do. The plaster used by 
Italians for making their images is the only kind 
that will answer. The reason probably is that the 
latter is sure to be fresh. 
Black Finish for Brass. — A writer in the 
"English Mechanic " gives the following as a good 
black finish for brass. Make the articles bright, 
then dip in aqua fortis, which must be thoroughly 
rinsed off with clean water. Then make the fol- 
lowing mixture: Hydrochloric acid, 6 lbs.; sulphate 
of iron, Jib.; white arsenic, 2" lb. Be careful to 
get all the ingredients pure. Let the articles lie in 
the mixture till black; take out and dry in hot 
sawdust, polish with black lead, and lacquer with 
green lacquer. 
Parasites on Canaries. — Almost every one of 
these household pets is annoyed with little par- 
asites, which render them weak by loss of blood 
and nervoTas irritation. To get rid of them we must 
study their habits. It is a curious fact that these 
parasites generally feed during the night, and 
leave the birds during the day. If the cages are 
provided with hollow perches, they will creep into 
them, and may be destroyed by boiling water. If 
the birds like to frequent a nest instead of a perch, 
