16 THE YOUNG 
you can keep your clay from drying by placing 
it in a box lined with ^vet clothes, or you may lay 
moist clothes on the obiect, and over this place 
an oil-skin or rubber cloth. The difficulty is that 
the weight of the wet cloth is apt to press the ob- 
ject out of shape. Artists found out long ago that 
the glycerine recipe is a ''sell," but our technical 
papers repeat the directions once a month at 
least, and our " books of recipes" faithfully copy 
them. 
Liquid for Tempeeing.— The following recipe 
was taken from . a journal in which I 
have great confidence: — 
To give iron a temper for cutting porphyry, 
make your iron red hot, and plunge it into water 
distilled from nettles, acanthus, and pilosella, or 
else in the juice pounded out from these plants. 
I have written to them for the common names 
of the plants, but have received no answer. Can 
you tell me? Blacksmith. 
Ans.—'SVe regret to be obliged to say that your 
confidence has been misplaced. The recipe is 
utterly worthless. As to the name of the plants, 
with the exception of the first, the author only 
gives one-half the name. This recipe is a very 
good sample of the thoughlessness of many of 
our scientific editors, who do not scrutinize 
closely the matter which they insert in their 
columns. The works of the older writers are 
filled with such trash, and men like Wendell 
Phillips tell us that if we could only find the pro- 
per name of the plant we would recover one of 
the lost arts. 
EXCHANGES. 
Only those who are j)'^(7r/}/ subscribers, and whose names 
are entered on our books have the privilege of inserting ex- 
changes. 
Exchanges must be on separate slips of paper or postal 
cards. If mixed with business letters or cards they cannot 
be used. 
Exchanges must not exceed thirty words. 
Buying and selling belong to the advertising department. 
We reserve the right to omit the exchange column, when 
we have not room for it, and the amount of space at our dis- 
posal will regulate the number of insertions given to each 
exchange, the preference being always given to those who 
have not previously used our columns. 
To exchange for a wood-turning lathe or offers, a Young 
America Self-inking Printinr Press, with type and outfit 
complete ; chnse 3x5 inches. Embury McLean, 318 Bloom- 
field St., Hoboken, N. J. 
What offers for " Our First Century," cost $7.00, bound 
in sheep, over 400 illustrations, i,coo pages; also small 
Ruby Magic Lantern, cost $1.50. Box 217, So. Manchester, 
Conn. 
Magic lantern, in good order, condensing lens, in. 
diameter, 8 slides. For small photographic camera or offers. 
H. A. Giddings, 4 Union Place, Classon Ave., Brooklyn. 
Printing press, type, etc., worth $13, for offers. E. G. 
Vogeley, loio Bradford St., Pittsburgh, Pa. 
Fifty canary birds, with and without crests ; fancy 
poultry, conch shells, strombus alatus. For small printing 
press, books on natural history, or offers. Frank Lattin, 
Gaines, N. Y. 
A good plain 7 shot revolver, 22 calibre, for a Students' 
inch or half-inch objective. Frank F. Colwell, Urbana, 
Ohio. 
Wanted, Printing press and t^i-pe, in good order, chase 
6x10, or larger; will give hardware, tools, scroll saw, or 
designs. Chas. E. Little, 59 Fulton St., New York. 
Photo outfit, tools, chemicals and apparatus, etc., etc.; 
wanted scientific books, apparatus, etc.; send lists. A. B. 
Campbell, Box 59, South Dayton, Catt. Co., N. Y. 
Stuffed birds, insects or job printing (cards, labels, etc.) 
for mounted objects for the microscope. James P. Melzer, 
Milford, N. H. 
SCIENTIST. 
A ring stand, filtering stand, calcium light jet and a gas 
holder, holding one cubic foot, for a phonograph. D P. 
Smith, 59 Park Place, New York. 
To exchange, Hugh Miller,s "Cruise of the 
Betsey," and " The Old Eed Sandstone." cloth 
bound geological books, for lathe, hammock, or 
"Gray's Manual of Botany." Gus. C. Spaeth, 
Mt. Carmel. Ills. 
F. F. F.. Lock Box 83, St. Johnsbury, Vermont, 
would like to exchange or correspond with per- 
sons interested in mineralogy. Oology, phila- 
tology, Indian relics, books, entomology, numis 
matology. etc. 
Wanted, a good printing press and type ; state 
what is wanted in exchange. H. A. Kinney, 
Hamlin, Brown Co., Kansas. 
I have a printing press and outfit (cost $15) to 
exchange for books, microscope, tent^ watch, or 
offers. Henry E. Jacobs. 53 Harvard Street, 
Boston, Mass. 
I have Vols. 2 and 3 of "Nests and Eggs of 
American Birds," to exchange for Vol. I of 
Young Scientist, or offers. N. B. Stone, Lock 
Box 9. Putnam. Conn. 
Wanted, a printing outfit or offers, in exchange 
for baritone cornet, air gun, and other things, a 
list of Avhich will be furnished upon application. 
E. S. Nixon. Jr., Box 315, Chattanooga, Tenn. 
To exchange, minerals, ores, shells, papers. 
nj||igazines, books, coins, starnps. for stamps, 
coins, minerals, stylographic pen. telephone, etc. 
A. M. Beveridge, P. O. Box 854, Appleton, Wis. 
Will exchange minerals for other minerals; 
state what specimens you desire. E. A. Eefsny- 
der, Phoenixville, Chester Co., Pa. 
Wanted, a good powerful second-hand micro- 
scope ; forward engraving of instrument, stating 
price, or what is wanted in exchange. L. D. 
Snook, Barrington, Yates Co., N. Y. 
Wanted, botanical specimens of Western. West 
Coast, and Southern ferns, in exchange for 
Northern species ; lists exchanged. H. N. John- 
son, Coeymans. N. Y. 
Wanted, copy of "Snowball's Elementary Na- 
tural Philosophy." M. B Tausy, Harrisburg, Pa. 
A new 2x4 engine, worth $60, for a first-class 
bicycle ; also a watch, revolver, and gas stove, for 
a 6x9 printing press, type, or offers. Geo. L. 
Lamson, La Fargeville, N. Y. 
To exchange, specimens in botany, oology, etc.. 
for those in other localities ; botanical corres- 
pondents desired. Arthur Fairbanks, St. Johns- 
bury. Vt. 
A German microscope, with 3 objectives and 5 
eye-pieces, condensing lens, etc., resolving Pleu- 
rosigma angulatum, will be exchanged for a 
first-class spectroscope. Clarence L. Speyers, 
50 West 17th St., New York. 
Shells and Corals,— These beautiful object? 
form favorite parlor ornaments for the mantel' 
piece and the what-not, but under such circum- 
stances they are generally looked upon as mere 
curiosities—" only this and nothing more." Mr. 
H. T. Woodman has taken a new departure in 
this direction, and has put up a number of boxes- 
none of which contain less than one hundred 
specimens— and which he sells for from 25 to 50 
cents each. This gives not only a number of 
objects of great beauty, but a series of specimens, 
the examination and comparison of which can- 
not fail to afford much useful and interesting in- 
formation. Our young friends who are at all 
interested in natural history cannot do better 
than to invest a few cents in one of these boxes.. 
Mr. Woodman may be found at 23 Clinton Place,. 
New York. 
