of gum mastic, and half a pint of

BURSTING,

The glass chimneys which are now in such general use, not only for oil lamps, but also for the burners of oil and coal gas, very frequently burst, owing sometimes to knots in the glass, when it is imperfectly annealed, but more frequently to an inequality of thickness at the lower end, which prevents the glass from expanding uniformly when heated. M. Cadet de Vaux informs us that, when the evil arises from the latter cause, it may be cured by making a cut with a diamond in the bottom of the tube. He states, that in an establishment where six lamps are lighted every day, and where this precaution was taken, there was not a single glass broken for nine years.

ANSWERS TO INQUIRIES.

NO. 147. COLOURING BRICKS. SIR,-I send you the following receipt for colouring Tiles:

Take one ounce of red lead to three ounces of manganese; get some strong clay, mix it with clean water until it is as thick as cream; pass it through a very fine sieve, then mix it with the lead and manganese. Let your tiles be dry; then pour it over them, and set them to dry. Do not let them touch each other in the setting, and keep them free from dust as much as possible in the kiln. I have only made one trial of this method, but it answered very well. To make your bricks and tiles of one, colour, mix all the different sorts of clay well together.

I am, Sir,
Yours respectfully,
FRANK BUTTON,
Brickmaker.

Colston,

Near Nottingham.

got for less expense at the colourshops than it can be made for, except in large quantities); put the above in a tin can, keep it in a very warm place, frequently shaking it, until dissolved; strain it, and keep it for use. Should you find it harder than you wish, you may add a little more turpentine varnish.

HENRY HOPE.

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NO. 137.-VIOLIN VARNISH.

rits of wine, to which put six ounces

BENSLEY,) Bolt-court, Fleet-street.

the dotted lines in this figure show the fire-place and flues, the arrow being in the direction of the flame to the chimney.

Figs. 5, 6, 7, 8, 9, 10, are plans and sections of several parts of the machinery, with different modifications.

Fig. 11, a plan of the ratchet-box, and part of the nave.

Fig. 12 is a top view of a plate fixed on the spindle of the steering-wheel, to indicate to the conductor the angle of obliquity of the two axles. The same letters and figures refer to the same parts in all the plans.

A represents the boiler, which is formed of a stout cast-iron or other suitable metal flue,inclosed in a wrought iron or copper case, as seen in section at fig. 3, where A is the place for fuel, and a, a, a, are parts of the flue, as seen in section; the top being formed,, as at fig. 4, into a number of shallow trays or receptacles for containing a small quantity of water in a state of being converted into steam, which is admitted from the reservoir by the small pipe, g, g; while b, b, b, is the outer wrought metal case for containing the steam for the use of the engine. centre flue. D, D, are the two cylinders, B is the chimney, arising from the which are fitted up with pistons and valves, or corks, in the usual way, for

the alternate action of steam above and below the pistons. The boiler being suspended on springs, d, the steam is conveyed from it to the engines through the helical pipe, e,which has that form given to it to allow the vibration of

Fig. 2 is a ground plan.

Fig. 3, a section, on an enlarged scale, of the boiler and machinery.

Fig. 4 exhibits the top of the boiler, with the feed-pipe, and receptacles for water, as will be afterwards explained:

joints. F is the cistern, containing water for one stage, say 50 to 80 gallons, and is made of strong copper, and air-tight, to sustain a pressure of about 60 pounds to the square inch. By e is denoted one or more air-pumps, which are worked by the beams of the engiues,