the framing; the earth may then be cautiously removed from under the wheels, and a length of rail introduced, taking care to bed it as securely as possible on the blockings previously laid down, without disturbing them; the same process should be repeated on the other side, and cross sleepers driven in under both rails to secure the foundation. As soon as the engine is in a vertical position and rails inserted under the wheels, a temporary railway may be laid down in continuation, and the engine again drawn on the main line. It will much facilitate the raising of the engine if the water is drawn away out of the boiler as soon as it is sufficiently cool.

In all cases of accident, involving the stoppage on the main line, it is of the highest importance that some person should immediately be sent back about three-quarters of a mile along the road, to give the proper signal of obstruction, and prevent any following train from running in unexpectedly.

The most essential personal qualifications of an engine-man are, sobriety and steadiness, activity, presence of mind, and unceasing watchfulness; and wherever these are combined with an accurate knowledge of the construction of a locomotive engine and the principles of its management, they tend in no small degree towards rendering railroads, what they properly are, the safest as well as the most agreeable mode of traveling.

Regulations for the first appointment of an Engine-man, adopted by the Directors of the London and Croydon Railway. 1840.

1. The candidate must not be under twenty-one years of age, and must produce a certificate of a sound constitution and steady habits. 2. He must be able to read and write, and understand the rudimental principles of mechanics.

3. It will be a great recommendation if he has served his time to any mechanical art, especially as a fitter of locomotive engines; and, if possible, he should produce testimonials stating his qualifications as such.

4. If the candidate has been a fitter or a stationary engine-man, he must, for several months at least, have been a fireman on a locomotive engine, under the direction of a steady and competent engineman; and before his appointment, he should produce a testimonial from the superintendent of locomotives, or at least from the engineman under whom he has served, stating full confidence in his acquaintance with the construction of an engine and the principles of its management.

5. If the candidate has not been a fitter or a stationary engine man, he must have served as a fireman for at least two years, and produce the testimonials named in the preceding rules.

6. If required by the board of directors, for greater security, the candidate must undergo an examination from their engineer, superintendent of locomotives, or other competent person, as to his knowledge of an engine and its management, and the general result of this examination must be committed to paper, signed by the examiner, and presented to the board.

7. The engineer or superintendent of locomotives of the railroad to which the candidate is desirous of being appointed, shall sign a certficate stating that he has conversed with him, has seen him drive, and has confidence in his steadiness and ability.

8. Before being allowed to take the entire charge of an engine and train, the candidate must drive for several days under the direction of an experienced engine-man, who must be on his engine, and certify to his ability.

9. All certificates and testimonials must be deposited with the secretary of the company, who will restore them to the owner on his leaving their service.

THE following Table, made expressly for the use of cotton and woolen mills, will be found very convenient for computing hastily the superficial contents of various sized cylinders.

TABLE

Showing the number of square feet of filleting cord required to cover the convex surface of any cylinder, from 1 inch diameter, varying by of an inch, to 20 inches diameter, and, in length, with variations from 18 inches to 49 inches.

EXPLANATION.-The length of any cylinder will be found at the head of each column, and the diameter in the left-hand column of the table.

Find the diameter of any cylinder, in inches, in the left-hand column of the table; then move to the right, on the same line, till you come under the length, in inches, and you will have the convex surface in square feet, and decimals of a foot.

Example. What is the convex surface of a cylinder, 5 inches diameter, and 40 inches in length?

Against 51, and under 40, stands 502, which is the true answer sought in square feet, and decimals of a foot. If a cylinder should exceed, in length, any provision which has been made in this table, its convex surface would be double what is shown for half its length. A cylinder 60 inches long would contain double the convex surface as is shown in the table to be the surface of one 30 inches long.

IRON.

1

85

Cast iron expands of its length for one degree of heat; the greatest change in the shade, in this climate, is of its length; exposed to the sun's rays, To; shrinks in cooling from to of its length; is crushed by a force of 93 000 lbs. upon a square inch; will bear, without permanent alteration, 15 300 lbs. upon a square inch, and an extension of 12 of its length.

Wrought iron expands 14300 of its length for one degree of heat; will bear on a square inch, without permanent alteration, 17.800 lbs., and an extension in length of T; cohesive force is diminished 3000 by an increase of 1 degree of heat.

1

Weight of modulus of elasticity, for a base of one square inch, 24 920 000 lbs. ; height of modulus of elasticity, 7 550.000 feet.

ANNEALING CAST IRON.

In the process of annealing cast iron, it is not desirable that the metal should be brought to any more than a red heat, as otherwise the smaller pieces and their bars might not only bend, but even melt. When the iron has become red hot, in a charcoal fire, it should be kept completely covered, and the fire allowed to go gradually out of its own accord. Or the iron, when red hot, may be buried in dry saw-dust, and in that state allowed to anneal. One great advantage of annealing cast iron is, that if it is afterwards subjected to a partial heating, it is less liable to warp than it would otherwise be. The character of cast iron is not in any way altered by annealing, except it is rendered more malleable. But the greatest benefit arising from this process will be seen from the following rule, which is exceedingly useful to iron founders, as by this means a great saving of expense may oftentimes be obtained in making new patterns.

To make a Casting of precisely the same Size of a broken Casting, without the original Pattern.

Rule. Put the pieces of the broken casting together and mould them, and cast from this mould.

This

When the casting is drawn from the sand, place it in a charcoal fire and anneal it as above described; it will expand to the original size of the pattern, and there remain in that expanded state. rule is of great importance to iron founders, as well as others, as by its observance much may be saved.