THE YOUNG SCIENTIST. 
131 
At the opposition of 1881-82, Schiaparelli again | 
had an opportunity of making: an examination ^ 
of this remarkable feature of the Martian topo- 
graphy, and made some discoveries concerning j 
them that are both curious and astonishing. | 
H(3 found, in tlie case of many of tlie canals of 
\which he had made faithful drawings during 
his earlier observations, that they had become 
•divided and subdivided by a number of parallel 
;iinos running through them. 
The most singular discovery is yet to be 
named. He was enabled to actually observe the 
progressive development and duplication of 
these canals in about twenty instances, between 
the 19th of January and the 24th of February. 
From the eminence of the observer there can 
■be no doubt of the entire reliability of these 
-astonishing observations. Schiaparelli has no- 
ticed other changes going on on the surface of 
our neighbor planet— notably, a considerable 
enlargement of one of the supposed oceanic 
bodies of Mars, known to astronomers as the 
Kaiser Sea, and the variable brightness of cer- 
tain other regions. 
The next opposition of Mars, which will take 
place on the 31st of January, 1884, will be antici- 
pated with much interest by astronomers, 
tjorae of the great telescopes, now in the course 
of construction, will by that time have been 
completed and erected, and, in the hands of dis- 
tinguished astronomers, it may be that the na- 
ture of the mysterious and pronounced changes 
now taking place on Mars may be unravelled. 
As they concern the celestial body, which, next 
to our own satellite, is nearest to the earth, the 
phenomena above noticed have universal in- 
terest. 
The article to be plated must be carefully 
cleansed and smoothed before commencing the 
operation, i'hau hold the end of a smooth cork 
an instant in the llame of your lamp, dip it in 
vinegar or salt and watei', and apply the gold 
powch^r with it to the metallic surface to be 
plated, rubbing it in with care and energy until 
the coating of gold is of the required thickness. 
Polish with a piece of manganese, or a bur- 
nisher wet with soft water in which a little soap 
has been dissolved. In performing this opera- 
tion great care must be taken not to allow the 
acid to touch the hands, especially if there is 
any bruis'e or scratch upon them. 
This recipe has been extensively copied, and 
always without a word of comment, and yet 
any person having the slightest knowledge of 
chemistry must know that it will not work- 
The process consists simply in preparing very 
finely divided metallic gold, but every one 
knows that this will not adhere to copper or 
brass by simple friction. The addition of a 
little mercury so as to form an amalgam, and 
the subsequent removal of the mercury by heat 
would convert it into a very fair recipe. 
Cold Gold Plating. 
We give the following, which professss to be 
taken from the Uhrmacher Zeitung as a fair 
sample of many of the recipes which find a place 
in the so-called technical journals : 
Silver, German silver, copper, brass, and 
pinchbeck will each take a fine plating and 
polish by the following method, requiring 
neither heat nor electricity during the opera- 
tion. 
To prepare the gold powder, dissolve some 
pure gold in nitro-muriatic acid vmtil the acid 
becomes so saturated with the metal that it 
ceases to absorb it; then soak up the liquid with 
fine linen rags, lay th^m aside till thoroughly 
dried, when they should be lighted and allowed 
to consume themselves quietly to ashes. In this 
way you procure pure gold in the finest possi- 
ble powder. 
If you wish to have your plating of a reddish 
tinge, copper must be added to the solution in 
the proportion of six parts gold to one part pure 
t5opper, dissolved in sixteen parts nitro-muriatic 
acid, dried and burned on linen rags as just de- 
scribed. 
Practical ^ints. 
The longest span of wire in the world is 
used for a telegraph in India over the river Kist- 
nah. It measures more than 6,000 feet and is 
stretched between two hills, each of which is 
1,200 feet high. 
Adhesive Cement.— Intimately mix finely- 
pulverized gum arabic with its weight of very 
finely powdered calcined alum. When mixed 
with a small quantity of water, it forms a cement 
which unites wood, paper, porcelain, glass and 
crockery very firmly. Must be kept dry in pow- 
der, and moistened only as needed. 
Removing- G-rease from Bird Skins.— Al- 
though it is not an easy task to remove grease ' 
either from the inside or outside of a bird skin, 
yet it can be accomplished by the following 
methods, seconded with a little patience: If the 
inside is greasy sprinkle liberally with plaster of 
Paris, and scrape with a blunt knife, renewing 
the piaster from time to time so as to thoroughly 
absorb the grease. Should a bird's feathers be 
greasy— and in a white bird the chances are 
nine to one that they will be— wash the greasy 
places freely with spirits of turpentine, and then 
pour on plaster, replacing it with fresh as soon 
as it has become saturated with turpentine, at 
the same time brushing and moving the feathers 
about in order that the plaster may penetrate. 
Finish by beating with a ligrht, elastic stick to re- 
move all the plaster. As maybe supposed, this 
is a somewhat tedious process, especially if the 
bird be large, but the results are excellent and 
well worth the trouble. The best time to cleanse 
a bird that is being mounted is after it has been 
wired and sewed up, but before placing on a 
perch. 
