1917.]. The Fourth Indian Science Congress. clxxi 



fined space, of the artificially and arbitrarily mounted propeller, by the 

 pull-balance, are fully set forth. 



Section 5. A complete conception of efficiency should allow full 

 weight to all the multiple factors of natural aspiration. 



Section 6. Factors affecting efficiency are fixed under the categories 

 of — space-elements, force-elements, time-elements, from the point of 

 view of the space distribution of thrusts, at any time, in the medium 

 agitated by the propeller. 



Section 7. Effect of the preceding factors on efficiency are fully 



analysed. Leading up to — 



Section^. The fundamental test of efficiency, which covers two 

 points: — (1) Is the thrust-system, in the natural space, maximum ? (2) 

 Does it grow in the minimum time ? 



Section 9. The measure of efficiency. The space-map i3 defined. 

 The construction of the space-map is explained. The measure is dis- 

 cussed ; and the apparatus, which was actually used with good results, 

 communicated. The gauge, which is the novel feature of the apparatus, 

 and which permits of the actual measurement of the turbulent motion, 

 is described. The working of the gauge is shown step-wise. 



Lastly the action of the guage is placed on a theoretically rigorous 

 footing, by basing it on the mathematical theory of an oscillating fluid 

 column and the attractive or repulsive force between spheres immersed 

 in it and placed close together, such oscillatory fluid-motion being the 

 type of turbulent-flow in the medium in which the propeller is at work. 



To conclude, the method records flow-effects just as they occur, 

 just where they occur. 



The Duration of School Life, a New Measure of Instruction 

 and a Test of Educational Administration.— By R. Little - 

 hailes. 



The method of calculating the duration of school life adopted by the 

 Government of India is criticised and shown to be imperfect. Three 

 other methods of calculating it are proposed and discussed. From the 

 value of the duration of school life thus calculated and from the number 

 of pupils under instruction at any time, a new measure of instruction is 

 proposed. From a comparison of the rate of variation of this new mea- 

 sure of instruction with the rate of variation in the number of pupils 

 under instruction, it is proposed to test the efficiency of the Educational 

 Rules or administration in force at the time ,of the comparison. The 

 variation in the cost of a unit of instruction is also referred to. Statistics 

 from the year 1895 up to date, i.e. for twenty years, are analysed. 



On certain Integral Functions defined by a Taylor's Series 

 with extensions to the case of the n — pb Power Series.— 

 By K. B. Madhava. 



Section of Chemistry. 



President— Dn. J. L. Simonsen. F.LC., Professor of Chemistry. 



Oentlemen, 



Presidency College, Madras, 

 r residential Address. 



I wish in the first place to say how ^.^^Jfig™^^ 

 • onour of being asked to Reside ^^^^^ •US^t^S 

 ^ZS£$££** iddr^ra i £ on* aft*r much consideration 



