New steam tables have been introduced by the author after the computation of equations constructed by himself, and values given in these tables lie within the region of tolerance of the Second International Skeleten Steam Tables, the international units as agreed upon by the First International Steam Table Conference being exclusively used. The new tables consist of five tables. Tables I and II are for saturated steam, the former being ananged in accordance with the temperature as basis, the latter with the pressure. Tables III and IV are auxiliary tables for superheated steam, while Table V gives values of specific volume, heat content and entropy of superheated steam in a range of temperatures from 30℃ to 550℃ and pressures from 0.03 kg/cm^2 to 250 kg/cm^2.(For details, see the Memoirs of the College of Engineering of the Kyoto Imperial University Vol.VII, No.3)

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The existing coal pear at Muroran is an elevated track of wooden construction with hoppers and chutes, which was built about twenty years ago. The Government Railways intended to reconstruct it with mechanical handling equipments to suit the increasing traffic, and to save the manual labour. The scheme of this plant is to handle 4,500,000 tons of coal yearly when completed ; in which 80% is to be loaded into ships from cars as cargo coal, and 20% to be delivered into barges and then loaded into ships as bunker coal. The plant now under construction is to handle about 3,000,000 tons of coal yearly, and it is expected to be put into operation early in the next year. The writer describes the general arrangement and the operation of this plant, particularly the special features of the loading equipments and coal storing bridge transporters. The loading equipments consist of two sets of mule haulage machines, revolving car dumpers, belt conveyors and loaders, having a capacity of 1,600 tons per hour ; these machines have several new and unique features, and all designed and constructed in this country.

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The authors attempt to indicate the degree of roughness of a finished surface of metal by three elements, i.e. the number of stripes per unit area or the number of cutting stroke per unit breadth, the inclination of grooved surface and the smoothness of inclined surface. The number of stripes is observed under a microscope by means of a negative print of the finished surface using a transparent celluloid plate. The inclination and smoothness of the grooved surface are measured by the "Arasa-meter" or a roughness meter, recently designed by the authors. Using a celluloid plate of milky white, a negative print of the finished surface is prepared and the reflection of light on the plate is measured by a photocell and is compared with that on a standard celluloid plate of the same kind finished by a glass plate with an optically true flat surface. The angle of incidence for the maximum reflection is also measured. The frictional resistance and the amount of leakage of oil between the two finished surfaces of metal were measured and they were compared with the degree of roughness observed as above. It is found that the cutting ability of tools can be expressed by the roughness of the grooved surface measured by the "Arasa-meter".

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The experiments were carried out to find the most economical cutting speed when a fine cut is employed in operating upon a series of steels with varying percentage of carbon. Wears appeared on the front clearance faces of tools were measured under microscopic observation. Time required for the begining of rapid wear of the tool was taken as the measure of durability, and the vertical cutting force was measured while the wear of the tool increased, a method described in the author's last paper having been used for this purpose.The results obtained are as follows : -(1) As to the cutting forces, the difference is slight, but regarding to the durability of the tool and the economical cutting speed it is remarkable in accordance with the compositions of steel.(2) In an economical cutting speed, in accordance with the increase of the wear of tool, the cutting force gradually increases and it reaches a maximum value of about 20% over the initial cutting force.(3) The temperature of the cutting edge is greatly affected not only by the cutting speed but also by the magnitude of wear of the tool. During a greater part of time of cutting by the edge, the wear gradually increases up to a certain value when it begins to increase rapidly.(4) The wear of cutting edge appears in many different forms according to the cutting speed, feed and material operated upon.

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In order to determine the minimum number of teeth in involute spur gearing, two cases are considered ; one of them irreversible, and the other reversible. For the irreversible gear wheels, the following equations are applicable, [numerical formula] where s_1=number of teeth in a pinion, n=number of pairs of teeth in contact, α=pressure angle, ε=gear ratio=R_2/R_1,R_2=radius of gear pitch circle, R_1=radius of pinion pitch circle, K=Σ_1'/(1+Σ_1'+1/ε), c=Σ_1'/Σ_2', Σ_1'=maximum specific sliding on the flank of pinion, Σ_2'=maximum specific sliding on the flank of gear, x_1=h_1p, x_2=h_2p, h_1=addendum of the pinion, h_2=addendum of the gear, and p=circular pitch. When ε and α are given, z_1 in equation (1) has a minimum value when n=1 and Σ_1'=Σ_2'=∞ ; therefore, by putting these values in equation (1) we can obtain the equation for z_1 giving the minimum value in this case, i.e., [numerical formula] A graphical representation of this equation is given in Fig.1 with a series of curves AB. From these curves it is evident that the following relations exist : -(1) When α is given, the value of the minimum number of teeth increases as ε decreases.(2) When ε is given, the value of the minimum number of teeth increases as α decreases.(3) 1-tooth gears are possible, and this case represents the least practical minimum number of teeth for irreversible gear wheels. Fig.2 gives an example of the gears corresponding to this case. For reversible gear wheels, in addition to eqs.(1), (2) and (3), the following conditions must be satisfied i.e., [figure][numerical formula] where t_1=T_<p2>/p, t_2=T_<p2>/p, ω_1=T_<α1>/T_<p1>, ω_2=T_<α2>/T_<p2>, T_<α1>=the thickness of tooth measured on the addendum circle of the pinion, T_<p1>=the same measured on the pitch circle of the pinion, T_<α2>=the same measured on the addendum circle of the gear, T_<p2>=the same measured on the pitch circle of the gear. In these equations, we can prove that if α and ε are given, z_1 has the minimum value when ω_1=ω_2=0,Σ_1'=∞ and n=1. Putting these conditions in eqs.(5) and (6), we have [numerical formula] A graphical representation of this equation is shown by the curves lying in the space CFEHIC of Fig.1. From these curves and those derived from the equations, we may arrive at the following conclusions : -(1) When α is given, the minimum number of teeth decreases as ε increases, and tends to a definite limiting value when ε tends to infinity.(2) When ε is given, the minimum number of teeth (z_1) exists in the case of Σ_2'=∞, and its values are as follows : -[table](3) Covering all the cases, the least minimum number of teeth is obtained at point C in Fig.1,where n=1,α=0,Σ_1'=Σ_2'=∞, ω_1=ω_2=0 and the number of teeth z_1=2'688. As it is obviously impossible to have a fractional number of teeth in a perfect gear, the next higher whole number, that is 3,must be taken as the practicable least number of teeth. A pair of 3-toothed gears thus obtained is shown in Fig.3.

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Das Problem der Drehfestigkeit von einem Winkeleisen mit endlichen und ungleichen Flanschen ist untersucht und mathematisch gelost von der "Zusammenfugungsmethode", die vom Verfasser erfunden und veroffentlicht ist in dem Aufsatz der die Warmeubergangsaufgabe in einem winkelformigen Leiter behandelt.(Diese Zeitschrift. Juni, 1931.)[figure] Das Prinzip dieser Methode ist folgende : -Der Winkeleisensquerschnitt (abb.1) ist eingeteilt in drei rechteckige Vierecke I, II u. III. ψbedeutet die Spannungsfunktion, die die fundamentale Gleichung ∂^2ψ/qx^2+∂^2ψ/∂y^2=-2Gτ uber dem Quersehnitte und die Grenzbedingung ψ=const=0 langs dem Umriss genugt. Angenommen ist ψ=f(y) langs der einteilenden Linie zwischen den Vierecken I u. II, und ψ=φ(x) zwischen II u. III. Erst, finde die Losung der fundamentaler Gleichung fur jedes eingeteilte Vierecke I, II u. III, die die Grenzbedingung von jedem selbst genugt! Dann, die Losungen ψ_I, ψ_<II> u. ψ_<III> seien zusammengefugt miteinander, um die Losung fur den fruhen Querschnitt so zu erhalten, dass ψ, die Kontinuitat erhaltend, uber dem ganzen Querschnitte austeilen wurde. Die angenommenen Funktionen f(y) u. φ(x) sind festgesetzt von der Bedingung, dass die Gradient von ψ normal zu der Zuammenfugungslinie zwischen I, II und II, III gleich sein mussten. Zum Beispiel, diese Methode ist angewandt fur den Winkelquerschnitt gezeigt in Abb.2,und die Resultate sind ausgestellt in Fig.1 u. 2,die die Verteilung von ψ, die Spannungslinien und die Spannungsgrosse langs dem Umrisse angeben.[figure] Ferner, wird es gesehen werden, dass von derselben Methode die mehrere Querschnitte, gewohnlich Walzeisenquerschnitte genannt, gelost werden mogen.

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Bei diesem Experiment handelt es sich um die Warmeleitung der Kuhlrippe im nichtstationaren Zustand welche von Dr. Prof. T.Suhara in Oyo Rikigaku Taikai, in November 1931 aufgelost wurde. Es wurde erstens die Temperaturverteilung der Rippe im Beharrungszustand bemessen und aus diesem Ergebnisse wurde die Warmeubergangszahl mittels der Analysis von Prof. Suhara bestimmt. Dann wurde die Rippe mit einer Periode geheizt, und die Amplituden der Temperaturschchwankung wurden gemessen und diese wurden mit den berechneten Werten verglichen.

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T. E. L. CO. sparking plugs have been designed and developed by the writer and are manufactured by the Tachikawa Engineering Laboratory Company, from which the plug derives its name. The factories of T. E. L. CO. were established in 1921,at Tachikawa Machi, near Tokyo, to make aircraft accessories and other instruments, by the present proprietor, Mr. M. Nosawa. In 1925-1926,the writer was able to produce sparking plugs with Mica insulator, commercially known as T. E. L. CO. M. 1. and M. 11., and has achieved several noteworthy successes on mail planes, between Tokyo, Osaka and Sendai. At the end of March, 1927,three types of T. E. L. CO. sparking plug were firs adopted by the Military Air Service as standard equipments, as they passed very severe tests which were carried out the Technical Division of Imperial Army, Tokorozawa. Now there are more than eight types of T. E. L. CO. sparking plugs which have been adopted in a large number by the Military Air Service and the Air Transport Company of Japan, with several records for the safety, soundness of construction and the low cost. The total number of types of all T. E. L. CO. sparking plugs which were actually designed and constructed, exceeds seventy three. So far as the question of production is concerned, a mass production system has been fully adopted throughout the shop, and the present capacity of production has been greatly increased to meet all demands. Parts such as plug shells and gland nuts are turned up by a number of gangs for turret lathes, and the grinding operation of insulators as well as assembly being conducted on line methods. Insulated electrodes are examined for the insulating property and gas leakage at various stages of manufacture, and after being assembled to shells, they are subjected to further leakage tests and spark tests under a high pressure. The advantages of using mica as insulating material, can not be over-estimated. Its chemical, electrical and mechanical properties are unique. It has an extremely good insulating resistance even at a very high temperature, as well as a high heat resisting property, an ample flexibility and a sufficient hardness. There are many kinds of mica, but they all belong to the same chemical family. They are silicates of alumina and alkalis, sometimes combined with magnesia and iron oxide. Although mica is one of the most universally distributed minerals on the globe, localities where the deposits consist of pieces large enough for sparking plugs are rare. India, America, Canada and Siberia produce most of mica used for sparking plugs, and a particular kind known as "RUBY" mica is the most suitable."BLACK" mica is also used for special sparking plugs, as it possesses a very high heat resisting property. Its laminar structure is well known, and the consequent absence of effective lateral cohesion is one of its outstanding characteristics. Great care has to be exercised in selecting mica, as it must be free of impurities as far as possible. The latest type of T. E. L. CO. sparking plug is M. 80. series, which has been designed for the particular use of modern high compression engines of air or water cooled types with a horse power between 400 and 800. M. 80. series embodies the same standards of design and workmanship as the previous model M. 54., the chief characteristics of M. 82. and M. 84. plugs being of the reliability, lightness and durability. In the history of mechanical engineering, the rapidity of progress in the development of aircraft engines is unparalleled. The requirement of the last few years inspired a great advance in the perfection of high compression and high power engines of both air-cooled and watercooled types, and consequently, severe conditions have been placed to the plugs, which necessitated quite special designs and materials to be used. At the immediate present, T. E. L. CO. M. 82. and M. 84. plugs consequently well

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This report deals with an example of solutions for stresses of a rectangular plate under concentric load, two opposite sides of which are placed freely on strong supports and the remaining two sides on elastic beams, and the calculated results were confirmed by experiments.

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