Table showing the quantity of Water per lineal foot in Pumps or Vertical Pipes of different diameters.

Diameter Number of Number of Diameter Number of Number of of pump gallons cubic feet gallons cubic feet

of pump

in inches. pr. lineal ft. pr. lineal ft. in inches. pr. lineal ft. pr.lineal ft.

Examples illustrative of the Utility of the Table. 1. Required the quantity of water lifted by each stroke of the bucket of a 9-inch pump, the length of the stroke being 24 feet.

3.068×2.25 6.903 gallons each stroke.

2. What length of stroke with

a 6-inch pump will be necessary to discharge 44 gallons of water per

M

minute, the number of strokes being 18 in the given time?

3. What must be the diameter capable of raising 25 cubic feet of water per minute, the length of the stroke being 2 feet, and making 16 effective strokes per minute?

It is by the oxygen of the atmosphere that combustion is supported. The common combustibles of nature are chiefly compounds of carbon and hydrogen, which, during combustion, combine with the oxygen of the atmosphere, and are converted into carbonic acid and watery vapour, different species of fuel requiring different quantities of oxygen. The quantity required for the combustion of a pound of coal varies from 2 to 3 lbs., according to the quality of the coal: 60 cubic feet of atmospheric air is necessary to produce 1 lb. of oxygen.

The pressure or fluid properties of the atmosphere oppose bodies in passing through it, the opposing resistance increasing as the square of the velocity of the body, and the resistance per square foot in fbs. as its velocity in feet per second, multiplied into 002288. Thus, suppose a locomotive engine in a still atmosphere, at a velocity of 25 miles per hour, presents a resisting frontage of 20 feet; required the amount of opposing resistance at that velocity.

25 miles per hour equal 36.67 feet per second.

Then 36 672x002288 × 20 61.5 lbs. constant opposing force.

Table of the force and common Appellations given to Winds at different velocities.

In order to gain the greatest amount of the wind's impulsive effect to produce rotary or circular motion by the sails of a wind-mill, the total surface of the sails presented to the wind ought to be about ths of the circle's surface which is formed by their motion, and each sail angled to the plane of motion as follows, the whip or back being divided into six equal parts. Distance from centre of motion 1 2 3 4 5 61 Smeaton's Angle with plane of motion... 18° 19 18 16 127 rule. By G. Forrester, Liverpool ......24° 21 18 14 9 3

RULES, TABLES, &c., RELATIVE TO BOILERS

AND THE STEAM ENGINE.

THE Boiler of a Steam Engine may be explained as that portion of the structure in which the vital principle of the engine is generated; consequently its construction is of the utmost importance, for upon the proper efficiency of the boiler depends in a great measure the efficiency of the engine.

Boilers not unfrequently, because of unavoidable peculiarities, are necessarily constructed of various forms; but for land or stationary engine boilers, if no thwarting circumstances intervene, either the waggon or cylindrical forms are commonly resorted to; the former for those of condensing engines, and the latter for those of the high pressure principle.

In the construction of boilers, much attention ought to be paid in avoiding thin films of water where the action of the fire is great, because it is neither consistent with safety, nor can there be the proper quantities of steam generated according to the surface exposed, unless under some extraordinary degree of pressure. Also convex surfaces, exposed to the action of the steam, unless properly supported, ought strenuously to be avoided. Large water spaces, concave surfaces, or straight plates securely stayed, with ample steam room, are the chief requisites to be attended to.

1. To determine the proper quantity of heating surface in a boiler for an engine with a cylinder of a given capacity, and steam at any density required.

Rule.-Multiply 375 times the area of the cylinder in feet by the velocity of the piston in feet per minute, and divide the product by the volume of steam to 1

of water at the density required (see Table, page 242), and the quotient is the amount of effective heating surface in square feet.

Ex. Required the amount of effective heating surface in a boiler for an engine whose cylinder is 4 square feet in area, and the piston's velocity 224 feet per minute, the pressure of the steam to equal 5 lbs. per square inch above the pressure of the atmosphere. =295 square feet nearly; the fire-grate being

375 × 45 × 224

1282

in accordance with the following rule.

Multiply the number of square feet of heating surface by 12, the product equal the area of fire-grate square feet, thus

in

:

295 × 12=354 square feet of furnace-bar.

Note.-By effective heating surface is meant horizontal surfaces over fire, flame, or heated air; vertical or side surfaces requiring about 13 ft. to equal in effect 1 of horizontal surface.

2. To determine the proper dimensions for a waggonshaped boiler, when the amount of effective heating surface in square feet is obtained by the preceding rule.

1. The bottom surface equal half the whole surface. 2. The length of the boiler equal twice the square root of bottom surface.

3. The width equal one-fourth the length; and 4. The height equal one-third the length.

Ex. Required the dimensions for a boiler of the waggon form that may present an effective heating surface of 295 square feet.

Bottom surface-295-2, or 147.5 square feet.

Note. The amount of side or vertical surface equal twice