The following test of delta - metal (forging) was made at Lloyds Proving House,
Cardiff:-

The stalk of a valve spindle-inch diameter at small end, drawn out of a 2-inch chill
cast delta- metal billet, was cut from the forging, and tested with results as per copy
below :-

(The sample was reduced in centre for testing.)

WHITE BRASS

§ 44. Alloys of copper and zinc containing less than 45 per cent of copper cease to have a yellow colour. The alloys containing from 40 down to 30 per cent of copper are silver-white, and with less than 30 per cent of copper the colour passes from gray to bluish-gray, having a greater resemblance to metallic zinc as the proportion of that metal is increased. The silver-white alloys break with a conchoidal fracture, and the more zinciferous alloys with a fracture more or less crystalline. In consequence of the brittle nature of white alloys they cannot be used for rolling and wire drawing, but some of them are used for pressed work, when too strong a pressure is not required. Some of them are known by special names, thus :

§ 45. Birmingham Platinum and Platinum Lead are used for certain castings, but the composition is variable, according to the taste of the manufacturer. The following will illustrate this point :

The above alloys are used for buttons by casting them in moulds giving sharp impressions, the letter or crest being subsequently brought out by careful pressing. Other alloys for buttons consist of—

§ 46. Sorel's Alloys.-These alloys are distinguished by great hardness and considerable tenacity. They cast well and can readily be detached from the mould. They are largely used for statuettes and other artistic work, which, after suitable bronzing, are brought into commerce as castbronze. The following mixtures are recommended :

Iron is used in the form of turnings, and melted with the copper and zinc under a layer of charcoal. But as zinc so readily volatilises it is advisable to employ zinc already containing iron, by which a more uniform alloy is obtained, with the minimum loss of zinc.

§ 47. Fontainemoreau's Bronzes. These so-called bronzes are said to answer well for chill-casting, the metal being poured into iron moulds. By this means the alloys are rendered more homogeneous, because the rapid cooling prevents the separation of the constituents in accordance with their respective densities. The highly crystalline nature of the zinc is changed by the addition of copper, iron, or lead. The following are the proportions used:

§ 48. These are copper-zinc alloys employed for joining the various parts of articles together by fusion. The solder must, therefore, have a lower melting point than the body to be soldered, but the fusing point of the solder should approach, as nearly as it conveniently can, to that of the article, as a more perfect and more tenacious junction may thus be effected. Brass solder belongs to the class known as hard solders, or brazing solders. It may be stated as a general rule that the melting point of copper-zinc alloys is higher in proportion to the amount of copper present, and therefore any quality of brass may be made into a suitable solder by adding zinc or copper as the case

may be. The alloy commonly used in soldering brass contains equal weights of copper and zinc. An easily fusible solder may be made with 34 copper and 66 zinc. In this case, however, it must be borne in mind that the joint would be much weaker than when the more difficultly fusible solder is employed, so that excess of zinc is to be avoided wherever possible. A readily fusible solder may be obtained by using 44 parts copper, 50 parts zinc, 4 parts tin, and 2 parts lead. Alloys containing lead are not to be recommended, since the lead tends to separate out and produce unsightly black spots, besides decreasing the strength of the joint. A good hard solder for the richer alloys of copper and zinc may be produced from 53 parts copper and 47 parts zinc. Brass solder is sometimes used for soldering iron and copper, and as these metals have a much higher melting point than brass, a much better quality of solder can be employed, and is indeed advisable in many cases, being much stronger. In these cases tin is often added as one of the ingredients, but it should be only sparingly used, as it increases the brittleness of the solder and thus becomes a source of weakness. The addition of tin to brass causes the yellow colour to pass into gray, or white, according to the content of tin employed, and mixtures may be obtained of a yellow, yellowish-white, and grayish-white colour. The following table indicates the different varieties:

In making solder it is very important that the constituent metals should be of good quality, as impurities seriously interfere with the colour, malleability, and strength of the solder; great care should also be taken to insure a thorough mixture, so that the alloys may be uniform in composition. Solder is often made by melting brass with the requisite addition of zinc, thereby insuring a more perfect union and less loss of zinc than is the case when zinc is

added to molten copper. Solder is most commonly used in the granulated form, which is effected by pouring the molten alloy into water, or by pounding it in an iron mortar when strongly heated.

The most suitable mode of preparing brass solder is to melt the brass rapidly in a crucible, the metal being covered with a layer of the best powdered charcoal, and when thoroughly fused, to add the zinc, which has previously been heated to near its melting point. Stir vigorously for a few minutes to insure a thorough incorporation of the contents, skim the dross from the surface, and then pour, taking care that no dross or charcoal is carried over with the metal into the mould, or into the water, as the case may be.

One method of granulating is to take the ingot of metal from the mould immediately it has solidified and pound vigorously in a large iron mortar. Or to first raise the ingot of solder to the requisite temperature over a charcoal fire, and then crush to powder in an iron mortar.

Some manufacturers pour the molten metal into a ladle, and empty the contents of the latter from a considerable height into cold water, the metal in its descent passing through a wet broom, or similar contrivance, so as to divide it into fragments. The granulated metal is afterwards sifted through sieves of different sized meshes, so as to obtain the grains of uniform size.

Another plan is to pour the molten metal on to the surface of a large iron ball, placed in a shallow pan containing cold water, so that the top of the ball projects above the