1. Handle carefully, avoiding a sudden jar or concussion, and be very careful, if any is spilt outside the can, to avoid striking it against any hard substance.

2. When solid, thaw out by placing the cans in a tub of warm water, not hotter than the wrist can bear, first pouring warm water into the can, and always remove the can before adding more hot water to the tub.

4

3. To fill Cartridges, &c.-Hold the cartridge to be filled over a tray, say two feet by three feet, the bottom of which should be overed with Plaster of Paris (which will not readily explode when saturated with Nitro-Glycerin.) The soiled Plaster of Paris should be frequently renewed.

4. If the Nitro-Glycerin in a liquid state is kept in store or magazine for some time, the crk should be loosely inserted, and a pint of cold water poured in each can, to be frequently poured off and replaced with fresh cold water in warm weather, taking care to retain the bladder under the cork. It is preferable, when ice can be procured, to congeal the Nitro-Glycerin.

5. Use Funnels (gutta-percha if it can be had) for filling water holes. Under no circumstances whatever attempt to tamp the drill holes; it is unnecessary, and may kill the man who attempts it.

6. Hot irons to warm the water, or soldering the cans, will be sure to cause explosions.

7. Never sledge or attempt drilling in a hole or seam where Nitro-Glycerin has been spilled; fire an exploder, which will effectually clear it up.

8. Never pour Nitro-Glycerin into a hole unless perfectly sure that it is a sound hole, or will hold water; if seamy always use cartridges.

9. To obtain the best results with Nitro-Glycerin, drill deep holes, 6 feet or more. Use powerful exploders and well insulated wires, It is cheaper to fire by electric battery with simultaneous explosion, than to fire several holes with tape fuse.

10. Look out after a blast for any unexplo 'ed cartridges lying around.

11. Never allow any but the most careful persons to handle or have charge of the Nitro-Glycerin, and insist upon the use of every precaution to prevent an accident or explosion.

12. Never allow empty Glycerin cans to be used for any other purpose, but destroy them by a fuse and exploder, or building a fire under them, first, however, removing them to a safe distance.

13. Examine your cans from time to time, and notice if, at the level of the Nitro-Glycerin, any pin-holes have eaten through; in such case procure a new can, or stone jar, and empty the contents out, not trusting your hold to the upper part of the can, lest it may give way.

14. When solid, or congealed, it is absolutely safe; if possible, therefore, any surplus should be stored surrounded with ice, since no explosion can take place whn it is solid.

THE ELECTRIC RAILROAD SIGNAL CO,

194 Fulton Street, New York,

Are now prepared to receive orders for the erection of their Improved and Perfected ELECTRIC SIGNALS, manufactured under the patents of F. L. POPE and S. C. HENDRICKSÓN. Our Improved

ELECTRIC SEMAPHORE

can be operated at any distance, and its indications are instantly and infallibly REPEATED BACK to the signalman on the same wire. For STATIONS, TUNNELS, BRIDGES, and Sections of SingLE TRACK, this Signal is invaluable. We also furnish an

AUTOMATIC BLOCK SYSTEM,

which is operated by the trains themselves, a section of the track being brought into the electric circuit. This system s the ON Y RELIABLE one for working automatic signals, and is covered by the original patent of F. L. POPE, July 16, 1872. Our Signals have been thorougly tested in practical service. We also design and erect to order, special Signals for

Draw-Bridges, Crossings, Station-Yards, Etc., Etc.

We invite the attention of PURCHASING AGENTS and RAILROAD TELEGRAPH SUPERINTENDENTS to our new patterns of

STANDARD TELEGRAPH INSTRUMENTS,

which have been designed EXPRESSLY FOR RAILROAD SERVICE.
They are of "ovel and elegant design, superior finish, and especially con-
structed for STRENGTH and DURABILITY.
Our magnets are all
wound with us:ed copper w re of 95 PER CENT conduce vity, and by a patented
process which adds 20 per ce t to their working strength.

Send for our Illustrated Catalogue and Price List of Instruments,
Supplies and Material.

0.

194 FULTON ST., NEW YORK. [P. O. Box 6010.]

The Grain is the same in Troy, Apothecaries and Avoirdupois Weights. The standard avoirdu o's pound is the weight of 27.7015 cubic inches of distilled water weighed in the air, at 35 85 degrees Fahr., barometer at 30 inches. 27.343 grains = 1 drachm.

1 = .0625 = .0039 .000139.000035.00000174 1.771846
1.0625 = .00223 = .000558

ton.

French grammes.

=

.000028 =28.34954

16=

256 =
7168 =
448= 28 =1
28672= 1782 =

16= 1

.0357

.00893

.25

112

= 4

=1

=

.05 1

The jeweler's Carat is equal, in the United States, to 3.2 grains; in London, to 3.17 grains; in Paris, to 3.18.

Pure Gold is worth

$20.67 per oz. Troy, or $18.84 per oz. Avoirdupois.

=

lbs. Avoirdupois.

Silver

$1.36

66
$1.24
$16,96 (C

In Troy and Apothecaries' weights, the grain, ounce, and pound are the same.

ELECTRICAL ENGINEERS.

TOWLE & UNGER M'F'G CO.

30 CORTLAND STREET, NEW YORK.

HAMILTON E. TOWLE, Treas.

WM. UNGER, Sup't.

MANUFACTURERS OF ALL KINDS OF

ELECTRICAL APPARATUS,

PRINTING, DIAL AND STANDARD TELEGRAPH INSTRUMENTS.

TOWLE'S PATENT

GRADE AND DRAINAGE LEVEL

Sent to any address on receipt of price, $15.00. Send for descriptive circular.

THE PRACTICAL APPLICATION OF

MAGNETISM TO MACHINERY A SPECIALTY.

Electric Railroad Signals, (Pope & Hendrickson's Patents.)

I knot or geographical mile 6082.66 feet = = €082.66 feet – 1851 mètres = 1.152 statute mile.

= 80

= .0125
1

20.116

= 1609.315

Sidereal Day 23 h., 56 m., 4.092 sec., in solar or mean time.
Solar Day (mean) 24 h., 3 m., 56.555 sec., in sideral time.
Sideral year, or revolution of the earth, 365.25635 solar days.
Solar or Calendar Year, 365,24224 solar days.