152 
THE YOUNG SCIENTIST. 
To Keep Pipes from Freezing—The only 
certain preventive is the removal of the water, 
and it is worth while to make provision for turning 
off the water during very severe nights, letting 
it on during the day time. We must not forget, 
however, that merely shutting off the water will 
not answer; the water must be let out of the pipes. 
To do this a small tap or petcock should be placed 
just above the main stopcock, or the latter should 
be made with a vent which allows the water above 
it to flow out when it is turned off. 
Ijemon Tree Wood. — A writer in the "Garden- 
er's Monthly" says that when in Rome, a few years 
ago, he was shown some work made out of the 
lemon tree that was considered almost as good as 
if made from box; and he makes the suggestion 
that a plantation of lemon trees for the wood, to 
say nothing of the fruit, would be profitable. The 
lemon tree is generally grown for fruit, but it would 
no doubt do well from a wood-growing point of 
view in less favorable climates. The lemon tree 
ought to do well at the South, and in many parts 
of California, and as boxwood is becoming quite 
scarce and expensive, the experiment is worth 
trying. 
Fair of the American Institute.— The 
large building in which this Fair is held, seems to 
be better filled than ever this year, and many of 
the articles on exhibition are of unusual interest. 
One of the great attractions is the electric Ught, 
with which the building is illuminated, thus giving 
those who desire to see this new mode of lighting 
an opportunity to do so. One of the most inter- 
esting features of the Fair is the machinery in 
motion, and the various industries, the operations 
of which are carried on in the building. This 
makes the Fair one of the most efficient educa- 
tional agencies in the city, and there is no place to 
which parents can take their children more profit- 
ably than to the American Institute Fair. 
Artificial Black Walnut — A Belgian journal 
says a new process has been applied to the manu- 
facture of artificial black walnut, by which ordinary 
wood has imparted to it the appearance of the 
most beautiful specimens of walnut, adapted to 
the very finest cabinet work. The wood, first 
thoroughly dried and warmed, is coated once or 
twice with a liquid composed of one part by weight 
of extract of walnut peel, dissolved in six parts of 
soft water, by heating it to boiling, and stirring. 
The wood thus treated is, when half dry, brushed 
with a solution of one part by weight of bichromate 
of potash in five parts of boiling water, and, after 
drying thoroughly, is rubbed and polished. The 
color is thus said to be fixed in the wood to a depth 
of one or two lines, and, in the case of red beech or 
alder, for instance, the walnut appearance is most 
perfect. 
A Good Hint for Pliotograpliers. Dr. Thos. 
Buzzard, who was recently undergoing the usual 
ordeal in a photographer's gallery, conceived the 
idea of suggesting some arrangement for relieving 
the eyes during the time it was necessary to keep 
them fixed upon a given object. In his own case 
he found that staring at a certain spot caused his 
vision to become indistinct, and surrounding ob- 
jects became lost, as in a thickening mist, whilst 
as the sitting was prolonged, a feeling of giddiness 
and even faintness was experienced. The plan he 
suggested was to draw upon a piece of card, about 
four inches in diameter, a clock-face, and add the 
usual Eoman figures. This card was fixed about 
eight feet distant, and when the sitting began he 
fixed his eyes upon the figure XII, and then upon 
the I, II, III, and so on all around the clock, shift- 
ing his gaze leisurely from one figure to the other. 
The result was the sitting ended without any sense 
of strain, and he seemed to have sat without an 
effort, while the slight change in the direction of 
vision required did not at all affect the accuracy of 
the portrait. 
Studio Glue.—Every one knows what a nuisance 
it is to "heat the glue-pot" when some small 
mend has to be made. And most people also know 
that all substitutes for glue are more or less fail- 
ures for wood work of all kinds; and, indeed, for 
most kinds of soft substances there is no cement 
that is so thoroughly satisfactory as glue. I have 
found an exceedingly simple way of using glue for 
small mends, and for general purposes where but a 
little is wanted at a time. The simplicity of the 
matter is so great as almost to need an apology for 
mentioning it, but its utility is so great that I must 
make that my excuse for writing about it. This is 
the method: Put a pinch of Nelson's shredded 
gelatine into a wide-mouthed bottle; put on it a 
very little water, and about one-fourth part of 
glacial acetic acid; put in a well-fitting cork. If 
the right quantity of water and acid be put, the 
gelatine will swell up into worm-like pieces, quite 
elastic, but at the same time, firm enough to be 
handled comfortably. The acid will make the pre- 
paration keep indefinitely. When required for use, 
take a small fragment of the swelled gelatine, and 
warm the end of it in the flame of a match or can- 
dle; it will immediately "run" into a flne clear 
glue, which can be applied at once direct to the 
article to be mended. The thing is done in half a 
minute, and is, moreover, done well, for the gela- 
tine so treated makes the very best and finest glue 
that can be had. I have no doubt this plan might 
be modified by dissolving a trace of chrome alum 
in the water used for moistening the gelatine, in 
which case, no doubt, the glue would become in- 
soluble when set. I have not tried this, as, for 
general purposes, there is no need for subsequent 
insolubility in glne.—Fhotographic News. 
