Nov., 1917.1 CURRENT TOPICS. 739

For lead extrusion, the necessary equipment consists of a multi- ple plunger pump, a hydraulic accumulator, and a hydraulic press with attachments. Briefly these attachments consist of a heavy steel cylinder with a die-holding arrangement on one end, the other end being open to form a close fit to the plunger or ram of the hydraulic press. In extruding lead wire, a large piece of lead is placed within this cylinder and the press started. Lead wire will flow continuously from the hole in the die until the ram reaches the end of its stroke; it is then withdrawn for a new supply of lead. During the two strokes of the ram there occurs no break in the lead wire, the second supply of lead welding perfectly to what remains of the initial charge. In producing lead pipe, a long arbor is used, the point of which enters the die in such a way as to form a ring-shaped nozzle which deter- mines the cross-section of the pipe.

Recognizing the possibilities of this process, ‘experiments were made with the object of producing brass rod and wire by the extru- sion process. Difficulties at once arose. It was found that to secure desired results, all the metal must be quite hot during the extruding, that hydraulic presses of great power were necessary, and that dies suitable for lead extrusion would not withstand the temperatures essential to successful results. These difficulties have, however, been overcome and a number of firms are now making brass rod by the extrusion process. A valuable feature of this process is the practica- bility of extruding the brass through odd-shaped dies to form cer- tain cross-sections very expensive to obtain by other methods.

Largest Ingot Mould Ever Made. ANON. (Mining and .Scio~- tific Press, vol. 115, No. 15, p. 543, October 13, IgI7.)-The largest ingot mould ever made has just been poured by the Bethlehem Steel Company at South Bethlehem, Pa. Its dimensions are 15 feet 7 inches high, with a mean diameter of 91% inches, its shape being octagonal and corrugated. At its thinnest section or point of corru- gation the thickness of the metal is 15 inches, and the heaviest section is 20% inches. A mould of this size is made so that steel can be poured into it to form ingots large enough to be reconverted into r6-inch and IS-inch guns. A steel ingot poured in this mould will weigh JOO,OOO pounds, and from it tubes and jackets for the large guns will be forged. Before the mould can be used large steel bands. 12 inches wide, must be shrunk around each end of the casting after it has cooled. Because of the necessity of pouring this large mould quickly, Bessemer pig-iron was melted in three large open-hearth steel furnaces and the melted iron suspended in ladles over the mould at one time. A continuous runner from the ladles was made so that the iron was thoroughly mixed before entering the mould. It took 340,000 pounds of pig-iron to pour the casting, not counting the 10,000 pounds needed later to fill up the sink-heads so as to take care of the natural shrinkage. The mould had to be left covered in the sand for a considerable time to completely cool. Two large

740 CURRENT TOPICS. [J. F. I.

Ioo-ton cranes were used to lift it from its pit and prepare it for transference to the open-hearth department, where it will be used regularly for casting ingots.

The French Official Horsepower Formula for Rating Auto- mobile Engines. EON. (TIM Autocar, vol. xxxix, No. 1145, p. 300, September 29, IgI7.)-The question of a formula which will give some fairly approximate idea or reasonable basis of comparison of the power capacity of an internal-combustion engine has long been of interest. In England it is well known that for taxation purposes the Government adopts the R.A.C. formula, D2 x N + 2.5, D being the cylinder diameter in inches and N the number of cylinders. The drawback to this formula is that no regard is paid to the question of the effect of varying piston stroke on the power development. ;Zc- cording to Cycke a$ad Automobile Industries, in France a new formula has bmeen issued by the Ministry of Public Works, and is now being employed by the Service des Mines for determining the amount of annual tax payable by car owners.

The new formula is H.P. = N x K x D2 r: L x n f 60 ; in which N is the number of cylinder; K a constant whose value is, for single cylinders o.ooz, for two cylinders 0.00017, for four cylinders 0.00015, and for more than four cylinders 0.00013 ; D the bore in centimetres, L the stroke in centimetres, and n the number of revolutions for the maximum speed of the car on the level. While on the basis of equal bore and stroke the French formula gives a lower rating in the case of two- and four-cylinder engines than the British, the intro- duction of the stroke in the formula has a marked upward effect on the horsepower rating of the engines. It is apparent, however, that one of the drawbacks of the new French formula will be the problem of deciding as to the number of engine revolutions to be taken into account, the maximum speed of the car depending on many variable quantities.

Suggested Reforms in Some Chemical Terms. C. HERING. (Proceedings of the American Electvochenzical Society, October 3-6, IgI7.)-Physical chemistry has done so much for the benefit of chemistry that chemists should in return recognize, readjust, and redefine some of their terms to bring gbout a better concordance with physical chemistry and a better consistency in pure chemis- try. The author’s purpose is to point out some of these deficiencies and to suggest a few reforms which would help to systematize these terms, make them more consistent with each other and with modern developments, and to simplify the conceptions involved. The scope of the discussion is limited to that branch of chemistry in which electrons are involved, no attempt being made to embrace organic chemistry and the chemistry of non-electrolytes.

A number of recommendations are made. These are: A more precise distinction should be made between different kinds of bonds.