THE YOUNG SCIENTIST. 
93 
what rotten ; so the less it is handled the 
better, though I have not the slightest 
fear in manipulating engravings of the 
largest size. Sometimes, if the engraving- 
be only slightly stained, half an hour is 
quite sufficient, but when quite brown I 
have left them in for as long as four 
hours. With a stronger solution the time 
required is much less. 
After all the stains are removed, and 
the paper has regained its pure whiteness, 
pour the solution out of the dish into a 
bottle (as this can be used over and over 
again— that is, several times until it be- 
comes discolored, when it must be dis- 
carded), then fill up the dish with water, 
changing frequently for about two hours, 
or, better still, place it in running water. 
When sufficiently washed it can be taken 
out and blotted off, and then hung up to 
dry, and, when perfectly dry, I find it ad- 
visable to iron on the back with a warm 
flat-iron ; but care must be taken not to 
have it too hot. When finished it will be 
as white as the first day it came from the 
press. The plan is very simple, and my 
advice is, try it.— Bintish Joimial of Pho- 
tography. 
Postage Stamp Frauds. 
EVEEY one must have noticed that 
periodically there comes up a demand 
for old postage stamps. People are asked 
to collect them, and various supremely 
silly reasons are given as excuses for the 
request. Now we are told that som'e one 
is going to paper a room with them, and 
that when the room is finished a sum 
equal to the value of all the stamps will 
be given to some benevolent institution ; 
at other times we are told that some rich 
idiot has i^romised to educate or endow, 
or do some other kind thing to some 
young girl if she can collect a million of 
postage stamps. And at one time we were 
told that the stamps had a real value, as 
the mucilage, the dye-stuff used in color- 
ing, and the paper itself all had a supe- 
rior value. 
It is hardly necessary to say that all 
these statements are false. The stamps 
are in almost every instance collected for 
fraudulent purposes. At one time cer- 
tain parties made a regular business of 
" washing " stamps and selling them as 
new. Many of the stamps, however, are 
so slightly soiled that they can readily be 
used a second time without any washing. 
It is also said that certain rogues in 
the post office use these old stamps to 
affix to letters from which the clean 
stamps have been removed. In view of 
these well-established facts, the Scientific 
American comes to the conclusion that 
the inventor who can make a really ser- 
viceable postage stamp that can be 
readily applied to an envelope, but which 
cannot be removed without the total ob- 
literation of the stamp, will have pro- 
duced a valuable improvement. By a 
serviceable postage stamp is meant one 
that will bear reasonable handling with- 
out injury, that has no poisonous quali- 
ties, that is easily applied, and, as just 
stated, that cannot be removed intact 
after it is once put on the letter. 
• ♦ . 
The American Institute Fair. 
THE annual fair of the American Insti- 
tute has been announced, and from 
the published plans and methods of the 
managers, we should say that the exhibi- 
tion this fall will be the best that has been 
held in many years. The managers seem 
to have taken the advice of the best 
friends of the Institute, and propose to 
make a special feature of processes and 
manufactures in operation. We have 
always held that the Institute has a 
higher mission to perform than to serve 
as a mere bazaar for advertising and sell- 
ing goods, though we have no objections 
to this feature provided it is kept in due 
subordination to the rest. The American 
Institute has always been one of the great 
educational agencies of the city, and this 
feature should be maintained by all legiti- 
mate effort. We are glad to see that the 
management takes this view of the mat- 
ter, and we feel sure that both for interest, 
brilliancy, and instructiveness, the com- 
ing fair will be ahead of anything that 
has yet been held. We hope our readers 
will make a note of it. 
— To wind a watch it is better to turn 
the hole downward, and let the small end 
of the key point upward. This will allow 
any little particles of dirt, metal or dust 
to drop out, and the watch will not need 
cleaning so often. 
