may be. The alloy commonly used in soldering br contains equal weights of copper and zinc. An easily fusi solder may be made with 34 copper and 66 zinc. In t case, however, it must be borne in mind that the joint wo be much weaker than when the more difficultly fusi solder is employed, so that excess of zinc is to be avoid wherever possible. A readily fusible solder may be obtai by using 44 parts copper, 50 parts zinc, 4 parts t and 2 parts lead. Alloys containing lead are not to recommended, since the lead tends to separate out a produce unsightly black spots, besides decreasing the streng of the joint. A good hard solder for the richer alloys copper and zinc may be produced from 53 parts cop and 47 parts zinc. Brass solder is sometimes used soldering iron and copper, and as these metals have a mu higher melting point than brass, a much better quality solder can be employed, and is indeed advisable in ma cases, being much stronger. In these cases tin is oft added as one of the ingredients, but it should be o sparingly used, as it increases the brittleness of the sold and thus becomes a source of weakness. The addition tin to brass causes the yellow colour to pass into gray, white, according to the content of tin employed, and m tures may be obtained of a yellow, yellowish-white, a grayish-white colour. The following table indicates t different varieties: : In making solder it is very important that metals should be of good quality, as imp interfere with the colour, malleability, and solder; great care should also be tak thorough mixture, so that the alloys may composition. Solder is often made by me the requisite addition of zinc, thereby insuri union and less loss of zinc than is the ca added to molten copper. Solder is most co the granulated form, which is effected molten alloy into water, or by pounding mortar when strongly heated. The most suitable mode of preparing br melt the brass rapidly in a crucible, the met with a layer of the best powdered char thoroughly fused, to add the zinc, which has heated to near its melting point. Stir few minutes to insure a thorough incorp contents, skim the dross from the surface, taking care that no dross or charcoal is ca the metal into the mould, or into the wat may be. One method of granulating is to take the from the mould immediately it has solidi vigorously in a large iron mortar. Or to first of solder to the requisite temperature over and then crush to powder in an iron mortar. Some manufacturers pour the molten met and empty the contents of the latter from height into cold water, the metal in its d through a wet broom, or similar contrivance, it into fragments. The granulated metal sifted through sieves of different sized me obtain the grains of uniform size. Another plan is to pour the molten me surface of a large iron ball, placed in a shallov ing cold water, so that the top of the ball proj surface of the water. The metal is thus broken up in small fragments of fairly uniform size. According to Krupp, the finest and most uniform produ is obtained in the following manner : "At some distance above the surface of the water, servi for the collection of the grains, a horizontal pipe is arrang which is connected either with a powerful forcing pump a water reservoir. Before pouring the metal the cock the pipe is opened, so that the jet of water issuing from t pipe is thrown in a horizontal direction over the ves containing the water. Upon this jet of water the molt metal is poured. The greater the force with which t water is forced from the pipe, the greater also the force w which the stream of melted metal is divided, and by t means it is possible, within certain limits, to obtain gra of a determined size." As will be seen from the abo description, the scattering of the stream of molten metal based on the same principle as that employed in diffusi fragrant liquids in the air. When solder is granulated by pouring into water, it necessary to remove the grains from the vessel as soon the operation is completed, and dry them quickly, so as avoid unnecessary oxidation. § 49. Allusion has previously been ma distinct modes of making brass, known the calamine and direct methods; the form exclusively used until within the last fifty but is now practically obsolete, at any rate i In the ancient or calamine method, met mixed with oxide of zinc and charcoal, an strongly heated for twelve hours or m zinc, reduced by the carbon and carbonic alloys with the copper forming brass. Such claimed to be of superior quality to that mad process, but as great improvement has take qualities of brass of late years, it is very d manufacture of calamine brass were to be res the value of the metal for most purposes would what the market can at present command. high quality of brass made by the old method maintained by exercising great care in the qua and copper employed, and selecting ores of position to produce a product of uniform an properties. The cost of production of calamin than that of brass made by the direct pro former method is much more tedious and requiring a much longer time than is consistent requirements, and for small founders is quite u CALAMINE BRASS § 50. For calamine brass the ores were sub preliminary treatment in order to remove as far other compounds, such as those of lead, an arsenic, which would injure the quality of the bra calamine was calcined to remove carbonic ac or other volatile matter, and form zinc oxide. cined ore was then ground in a mill, any gale |