THE YOUNG SCIENTIST. 
888 
i'dciitifit lltiws. 
—The thirty-second meeting of the American 
Association for the Advancement of Science was 
held at Minneapolis, Minn., beginning August 
15th, and closing August 2lst. Prof. C. A. Young, 
of Princeton, presided. 
—When a kerosene lamp is turned down low, 
the small flame is not sufficient to cause draft 
enough to ensure perfect combustion, and the 
result is the diffusion of vapors, the effects of 
which upon the health are well known to be evil. 
It is not a safe practice. 
—Sea water differs a little in weight at different 
places, but at the same spot it is nearly the same 
at all depths. It may be estimated at sixty-four 
pounds to the cubic foot, or pounds per cubic 
foot more than fresh water. The additional 
weight is chiefly common salt. Salt water freezes 
at 27° Fahrenheit. 
—A new vegetable parasite, Haplococcus reticu- 
latus, has been recently discovered in pork by Dr. 
Zopf. It occurs in from thirty to forty per cent, 
of the animals examined. Would it not be well 
if we paid more attention to the sanitary legisla- 
tion of Moses, a fragment of the ancient medical 
law of Egppt ? 
—The Volta prize of $6,000 will be awarded by 
the Academy of Sciences, Paris, in December, 
1887, under the decree of June 11, 1882, for the dis- 
covery or invention of whatever shall render 
electricity applicable economically to one of the 
following objects: Heat, light, chemical action, 
mechanical force, the transmission of messages, 
or the treatment of sick persons. 
—Prof. W. P. Barrett, of Dublin, has been mak- 
ing some interesting experiments to test the cor- 
rectness of the discovery claimed to have been 
made by the late Baron von Reichenbach, viz., 
that a peculiar luminous effect resembling a faint 
electric discharge in rarifled air, emanated from 
the poles of a magnet, and was rendered visible 
in a perfectly darkened room. These new ex- 
periments confirm those of Reichenbach. 
—London papers say that "the Secretary to the 
Eoyal Botanical Society recently tried the novel 
experiment of planting sea weeds in ordinary 
earth. It would naturally be supposed that these 
ocean plants would not flourish away from their 
native element; but this is not the case, most of 
the specimens planted having grown admirably 
in soil which is constantly kept in a moist condi- 
tion." The result is both curious and suggestive, 
and worthy of trial this side of the ocean. 
—An interesting experiment, illustrating the 
force of inertia and molecular resistance, is given 
in La Nature. It was first performed, and with 
a practical purpose, by a Corsican, under the 
second empire. Place a sealed piece of wax on 
an anvil, or well-siipiiortf^l iron plate, and over 
it a round ball of cast lo;;*! (not compressed), of 
diameter corresponding to its width. Now give 
the ball a sudden violent blow with a hammer. 
The flattened ball is found to have taken the im- 
pression of the sealed wax in its least details, 
and without breaking it (if the experiment is pro- 
perly done). With the aid of this matrix the seal 
may be copied. 
—Researches relating to sounds produced by a 
stream flowing through a circular hole at the 
lower end of a long tube containing liquid have' 
shown that the pitch does not change gradually^ 
but that a deflnite number of distinct notes are 
heard successively as the liquid column shortens- 
by the outflow. The pitch depends on the length 
of the liquid column and on the velocity of efflux. 
The number of vibrations is proportional to the- 
velocity of efflux, and the sound is pure only 
when the sound of the vein is one of the proper 
sounds of the liquid column. A column of con- 
stant length gives notes in a harmonic series. 
When the sound is reinforced by the column of 
air above it becomes quite loud. If the walls of 
the tube are prevented from vibrating, the sound 
ceases. The relative velocity of sound in differ- 
ent liquids may be determined by flnding the 
lengths of the columns of liquid which give the 
s>ame note, and the results thus obtained will be 
found to agree very well with determinations by 
other methods. 

iPriittital Jmts. 
—To make a black dye for wood, flrst sponge 
the wood with a solution of chlorhydrate of ani- 
line in water, to which a small quantity of copper 
chloride is added. Allow it to dry, and go over it 
with a solution of potassium bichromate. Repeat 
the process two or three times, and the 'wood will 
take a fine black color, unaffected by light or 
chemicals. 
—The government method prescribed for 
cleaning brass, and in use at all the United States 
arsenals is said to be the best in the world. The 
plan is to make a mixture of one part common 
nitric acid, and one-half part sulphuric acid in a 
stone jar, having also ready a pail of fresh water 
and a box of sawdust. The articles to be treated 
are dipped into the acid, then removed into the 
water, and finally rubbed with sawdust. This 
immediately changes them to a brilliant color. 
If the brass has become greasy, it is flrst dipped 
into a strong solution of potash or soda in warm 
water ; this dissolves the grease, so that the acid 
has free power to act. 
~A new screen, or corner stand, consists of an 
excellent imitation of a turf with a portion of a 
maliogany picket fence and gate arising from it. 
The gate is padlocked with a steel hasp and lock, 
and has steel hinges. Over the gate climbs a fox 
having in his mouth a hare that he has evidently 
caught in the garden, from which he would 
escape. A vine growing up on either side the 
