## The operative mechanic's workshop companion, and the scientific gentleman's practical assistant |

### From inside the book

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Page 154

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**dissolves**the metallic oxides and prepares them to combine with silex . Most of the metals combined with chlorine are very volatile , and in assays , other than those of the precious metals , salt is inadmissible . Saltpetre is ... Page 155

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**dissolve**the salt , and then exposed to evaporation under constant stirring . When dry , the contents are gently heated in an iron pot with a concave bottom , and as soon as any signs of melting are perceptible , the mass is diligently ... Page 156

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**dissolved**in the semi - fluid sulphuret , and an alloy is obtained , disseminated in small globules through the mass ...**dissolves**, the salt is extracted , and there remains in the vessel , a black , fine powder , which feels like ... Page 157

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**dissolved**the slag in warm water , sup- posing that all the gold was contained in the alkaline sulphuretted solution . But this was a mistake : gold is soluble only in alkalies which contain a large quan- tity of sulphur . Sulphur must ... Page 159

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**dissolves**them very readily . In all cases , therefore , where we have to deal with metals or metallic oxides , either one ...**dissolved**gold in contact with the lead , and it is absorbed by it . Metals and Gold . - When other metals are ...### Common terms and phrases

9 inches affinity alkaline alloy antimony Application assay avoirdupois BAR IRON beam bisect boiler breadth Broad carbonic acid cast iron centre chord Circum circumference contains copper crucible cube cubic feet cubic inches cupel cylinder decimal describe the arc Diam dissolved distance ditto draw the line feet diameter fluid flux frustum fusible gallons given circle globule gold gray iron heat hence hoop inches diameter lever line A B lineal foot litharge melted metallic lead Multiply number of teeth obtained operation oxide oxide of iron oxide of lead oxygen parallel perpendicular pinion pitch platinum potash produced pure quantity quired quotient equal radius rectangle right angles rule Rule.-Multiply saltpetre screw side silex silicate silver slag smelting soda solid square feet square inches square root steam sulphur sulphuret Table thickness tion triangle velocity weight wheel width yards zinc

### Popular passages

Page 188 - MECHANICAL POWERS are certain simple instruments employed in raising greater weights, or overcoming greater resistance than could be effected by the direct application of natural strength. They are usually accounted six in number; viz. the Lever, the Wheel and Axle, the Pulley, the Inclined Plane, the Wedge, and the Screw.

Page 27 - From half the sum of the three sides, subtract each side severally; multiply the half sum, and the three remainders together, and the square root of the product will be the area required. Example. — Required the area of a triangle, whose sides are 50, 40, and 30 feet. 50 + 40+30 ; — 60, half the sum of the three sides.

Page 39 - To twice the length of the base add the length of the edge ; multiply the sum by the breadth of the base, and by one-sixth of the height.

Page 126 - To find the absolute strength of a rectangular beam, when fixed at one end and loaded at the other. RULE. Multiply the value of S by the depth of the beam, and by the area of its section, both in inches: divide the product by the leverage in inches, and the quotient equal the absolute strength of the beam in Ibs.

Page 129 - ... by compression is different according to the proportion between its length and area of its cross section ; and supposing the form that of a cylinder whose length is less- than seven or eight times its diameter, it is impossible to bend it by any force applied longitudinally, as it will be destroyed by splitting before that bending can take place; but when the length exceeds this, the column will bend under a certain load, and be ultimately destroyed by a similar kind of action to that which has...

Page 270 - To find the mimber indicated by a given logarithm. Look for the decimal part of the given logarithm in the different columns, and if it cannot be found exactly, take the next less. Then under N in the left-hand column, and in a line with the logarithm found, are three figures of the number required, and on the top of the column in which the found logarithm stands is one figure more ; i place the decimal point as indicated by the logarithmic index, ! which determines the sum, properly valued, as required.

Page 16 - CUBIC MEASURE 1728 cubic inches = 1 cubic foot 27 cubic feet = 1 cubic yard...

Page 246 - ... reckoning from that point of the stroke where the steam of uniform elastic force is cut off : but it is more properly the force which steam is capable of exerting, when expanded to a known number of times its original bulk. And condensation, here understood, is the abstraction or reduction of heat by another body, and consequently not properly a contained property of the steam, but an effect produced by combined agency, in which steam is the principal ; because any colder body will extract the...

Page 269 - The whole numbers of the series of logarithms, as 1, y, 3, &c., are called the indices, or characteristics of the logarithm, and which must be added to the logarithm obtained by the Table, in proportion to the number of figures contained in the given sum. Thus, suppose the logarithm be required for a sum of only two figures, the index is 1 ; if of three figures, the index is 2^ and if of four figures, the index is 3, &c.

Page 245 - In the heating of buildings, its economy, efficiency, and simplicity of application are alike acknowledged; the steam being simply conducted through all the departments by pipes, by extent of circulation condenses — the latent heat being thus given to the pipes, and diffused by radiation. In boiling, its efficiency is considerably increased, if advantage be taken of sufficiently inclosing the fluid, and reducing the pressure on its surface, by means of an air-pump.