containing 60 to 70 per cent copper are colour. The composition most generally used per cent copper and 33.4 per cent zinc, English standard brass. It works excell rolls and hammer, and may be used also fo Cast-brass generally contains more zinc than be worked into sheet or drawn into wire a therefore more fusible. Moreover, the m selected with such care as is the case with and wire drawing, so that cast-brass is ofte than rolled brass, a large quantity of scrap Imelted with new metal. The most common lead, tin, and iron. These metals are disadvantage, for lead is generally added to from 1 to 2 per cent in brass required for tur as it gives sharpness to the metal and preven tools. The presence of a little tin is an a hardness is requisite, as in the case of bush A little iron hardens brass, and tends to incre and elasticity. But it is not advisable to in other than copper and zinc, unless for speci mentioned above. It should be borne in min beneficial the addition of lead, tin, or iron ma cases, the simultaneous presence of two or all is generally injurious, whatever the action o may be when present alone in the brass. In stated as a general rule, not without exceptions of two metals is more stable than that of t and the greater the number of metals alloyed greater will be the difficulty in obtaining unif castings. Lead especially has a tendency to from the mixture in cooling, producing unsight especially when present to the extent of 2 or n

When the metal is cast in a large mass, oare of considerable size, it is found that as the m a greater proportion of copper is found in the than in the upper part of the casting, and the

liable to be deeper in colour below than above. The stituents of an alloy of two or more metals tend to sep according to their respective densities, and the more n ous the constituents, and the greater the difference of specific gravities, the more marked will this tendency but when the metals are in chemical combination with other, no such separation will take place.

To test the difference in composition at top and b of cast-brass the two following experiments with accompanying analyses were made by the author. Dif varieties of brass were remelted together, so as to form different qualities of brass, and cast into upright taperin moulds 4 inches high and about inch square.

TABLE OF DIFFERENT QUALITIES OF ORDINARY CAST-BRA
DETERMINED BY ANALYSIS OF COMMERCIAL SAMPLES

of the

mari

an all

Tmore

her, the

Sour

English clock

67.0

⚫04

metal

English brass

2

24

1122

common)

Brass employed for the production of quires to possess other properties than the to be filed and turned in the lathe. It liquid when melted, and not in any degree will readily flow into the minutest and crevices of the mould, and the texture mus and uniform throughout. Moreover, as suc ally require to be sound and free from pinh capable of remaining thinly liquid until ne which it solidifies, so that the metal may b lowest possible temperature, thus enabling gases, absorbed during the melting, to esca possible before pouring. When the castin subsequently gilded, it has been found that is similar in colour to gold, it requires less the desired effect than when the brass is of colour. For this reason brass of reddish-y preferred. The French have brought the articles, as well as larger articles, to a high fection; clock-cases, statuettes, and other mental work are manufactured by them o scale. The alloys used for these purposes bronze, but they are generally brass, with a little lead and tin, which impart to the met colour. The following are the proportions us the French mixtures :

The above alloys can be readily cast, worked

turning tools, and readily gilt.

De fine-gr

astings s, it mus

the poin oured at T and

as mutt

have to n the m

to pr Dale yell

ng

colom

ee of

of t

stic or

extens

ten calle

dition a onze-li

a few

These alloys are distinguished by a beautiful gold which very closely resembles that of gold alloys. Th very ductile and tenacious, can readily be, stampe rolled, and admit of a fine polish. According to recipe orëide is prepared in the following manner : 100 parts of copper and add, with constant stirring, of magnesia, 3-6 parts of sal-ammoniac, 18 parts of lim 9 parts of crude tartar. Stir again thoroughly, and add 17 parts of granulated zinc, and after mixing i the copper by vigorous stirring, keep the alloy liqu one hour. Then remove the cover of dross, and po the alloy."

gold

§ 31. Talmi or Talmi Gold.-Also termed Aby

...

Talmi gold is the name given by the French, w the foregoing alloys for cheap jewellery, which is guished by good workmanship, great durability, beautiful golden colour. The colour is retained for siderable time, as it possesses a thin coating of gold, welded to the alloy by rolling, and when the gold is cient thickness the characteristic appearance may be r for years without alteration. But many cheap imi

are manufactured and sold under this name which co common brass, gilded with a thin coating of gold.

§ 32. Tournay's Alloy is also used i cheap jewellery, as well as for buttons ornaments. It is composed of 82.5 part

parts of zinc.

§ 33. Mannheim Gold, Similor, Pri composition of this alloy varies considera from the following analyses of three sam

The first has a yellowish-red tint, and deeper red. Similor has been much used other stamped work requiring a reddish ca

§ 34. Tombac.--As stated on a previ is a name applied to alloys which by so are termed prince's metal, similor, and Man name is used for alloys so widely differen and properties as to lose any significan formerly possessed, and strikingly illustrate of adopting Dr. Percy's proposition, that th of copper and zinc should be designated by composition. The following table will show of different mixtures: