April 30, 1896J 



NATURE 



623 



the past few years. In London alone the Technical Education 

 Board of the London County Council, and the Central (lovern- 

 inc; Body of the City Parochial Charities are spendinjj about 

 ^120,000 annually on technical education; and, probably, an 

 equal amount is being spent in the same direction by the 

 Livery Companies of London through the Institute or by 

 individual action. Apart from the City and Guilds of London 

 Institute, mention may be made of the Goldsmiths' Company's 

 Institute, at New Cross ; the support by the Drapers' Company 

 of the People's Palace; and of the Skinners' and Saddlers' 

 Companies of the Northampton Institute ; the Carpenters' 

 Company's Schools at Stratford and Great Titchfield Street ; the 

 Tanning School, recently established by the Leathersellers' 

 Company in the Borough ; and the technical schools and textile 

 departments in Leeds, Bradford, Huddersfield, Halifax, and 

 other towns in the north of England supported by the Cloth- 

 workers' Company, as a few of the institutions of a specially 

 technical character to which individual Companies are devoting 

 their funds. From a table given in the report to show the 

 amount of the donations to the funds of the Institute since its 

 foundation, we have extracted the following totals, running into 

 four or more figures, which to some extent supplement the 

 information given in a recent article on the grants of the City 

 Companies to education and research. Goldsmiths' Company, 

 ^^83,064 ; Clothworkers' Company, ;^7i,500; Fishmongers' 

 Company, ;[^70,550 ; Drapers' Company, 250,5oo ; Mercers' 

 Company, ;{i'50,ooo ; Skinners' Company, ;^25,835 ; Grocers' 

 Company, ;^i9,ooo ; Corporation of London, ^15,50x3 ; Salters' 

 Company, ;^I5,I38; Merchant Taylors' Company, .^^14,657; 

 Leathersellers' Company, ^10,105 ; Carpenters' Company, 

 /,8i55 ; Armourers' and Braziers' Company, ^7700; Iron- 

 mongers' Company, ;^5973 ; Cordwainers' Company, ;[f 5878 ; 

 Saddlers' Company, ;i^56oo ; Dyers' Company, ^^4646 ; 

 Coopers' Company, £2'jjo ; Vintners' Company, ;J2500 ; 

 Pewterers' Company, ^^2019 ; Plaisterers' Company, £i'^2>7 ? 

 Cutlers' Company, ;ii^i386. The present report furnishes the 

 City Companies with food for congratulation upon the results 

 of the generous provision they have made for technical 

 education. 



SOCIETIES AND ACADEMIES. 



London. 

 Physical Society, April 24. — Captain W. de W. Abney, 

 President, in the chair. — .\ paper by Mr. R. A. Lehfeld, on 

 symbolism in thermodynamics, was, in the absence of the author, 

 read by the Secretary. The author proposes a system of about 

 twenty-four separate symbols for the different quantities in thermo- 

 dynamics. Prof Silvanus Thompson said he was not at all favour- 

 ably impressed by the symbols proposed. In particular, it was 

 tiecoming usual to restrict the use of Greek letters to the repre- 

 sentation of specific quantities or angles, and the author's 

 [iroposal seemed in this way a retrograde step. Prof Perry said 

 he did not care for the suggested symbols. Mr. Elder thought 

 the author's system woukl be a very severe tax on the memory, 

 for he did not make use of suffixes, as was ordinarily done, 

 which in a great measure define the symbol to which they are 

 attached. — Mr. Appleyard read a paper on the adjustment of the 

 Kelvin Bridge. In a recent paper read before the Society, Mr. 

 Reeves had described a modified form of Kelvin Bridge, in 

 which a double adjustment was necessary. The author proposes 

 t(i employ two wires stretched side by side, with a sliding contact 

 in connection with the galvanometer on each. These contacts 

 :ire rigidly connected together, so that the segments into which 



ne wire is divided necessarily bear to one another the same 

 i.uio as do the segments of the other wire. Hence a single 

 adjustment is sufficient to give balance. Mr. Reeves said that 



I )parently the author had completely missed the object of his 

 nhe speaker's) paper. For the object there aimed at was to 

 make use of such sets of resistance coils as are always to be 

 found in any laboratory. In the author's arrangement it would 

 be necessary to carefully calibrate the two wires, and also, since 

 the resistances used must neceesarily be small, to determine the 

 resistance of the contacts. Prof. Ayrton (communicated) said the 

 author's suggestion was ingenious, but did not obviate the 

 necessity for much of Mr. Reeves' "addition;'" Further, Mr. 

 Reeves' proposal to employ ordinary resistance boxes was not 

 made because such resistances are absolutely necessary, but 

 because, since they are to be found in any electrical labora- 



tory, their use saves the expense of such a wire resistance 

 accuratelycalibratedasMr. Appleyard employs. Mr. Appleyard, 

 in his reply, said that his instrument was designed for use in a 

 factory where the time saved in making a series of tests was of 

 more importance than the cost of the instrument — Mr. J. Frith 

 read a paper on the effect of wave-form on the alternate 

 current arc. The author finds that an arc has the 

 power of modifying the wave-form in a circuit in which it is 

 included. Thus in the case of a dynamo for which, on open 

 circuit, the curve of E.M.F. was decidedly peaked, it war, found 

 that when this dynamo was employed to feed an arc that the 

 curve became changed to a flat-topped form. It is interesting 

 to remember that the candle-power of the arc is greater when 

 the wave-form is flat-topped than when it is peaked. By alter- 

 ing the resistance in series with the arc it is possible to alter the 

 character of the curve, for as the resistance in series with the 

 arc increases the arc affects the wave-form less and less. In 

 some recent experiments described by Dr. Fleming, a resistance 

 of about 7 ohms was used in series with the arc, so that the 

 wave-form of the generator, which is not an efficient form, was 

 forced on the arc. In practice, however, where a resistance is 

 not used in series with the arc, this is not the case, and the dif- 

 ferences between the efficiency obtained for alternate current 

 arcs in the laboratory and that claimed in practice may thus be 

 accounted for. — Mr. Blakesley said it seemed as if the more 

 nearly the alternate current resembles a direct current, i.e. the 

 longer in each period the current remains constant, the greater is 

 the efficiency of the arc. — Mr. Price asked what was the cause of 

 the reaction of the arc on the wave-form. — Mr. Tremlett Carter 

 asked whether previous observers' results were vitiated by this 

 action of the arc on the wave-form .•' — Prof. Ayrton (communi- 

 cated) considered the author's suggestion of great importance as 

 bearing on the question of the efficiency of the alternate current 

 arc. — Prof S. P. Thompson said that the dynamo employed by 

 the author was one in which there was a large quantity of iron 

 in the armature, so that the self-induction was large. Was it not 

 on account of this large coefficient of self-induction, which would 

 tend to keep the current constant, that the arc was able to alter 

 the wave-curve ? If an arc is connected to the mains of a supply 

 station in which a number of machines in parallel are feeding a 

 number of lamps, would the arc still be able to affect the wave- 

 form of the current ? — Mr. Tremlett Carter asked if the author 

 had tried the effect of replacing the arc by a resistance such that 

 it would absorb the same volts as did the arc, and comparing the 

 curves for the current and impressed P.D. with those obtained 

 with the arc. — The author, in his reply, said that the effect of 

 the self-induction of the machine was shown in the curves. 

 Current curves had not been taken with the arc straight on the 

 machine. The current and self-induction were the same for all 

 the curves, the voltage of the machine being increased by 

 increasing the field when a resistance was placed in series with 

 the arc. When, as is commonly the case, special machines are 

 used to supply arcs, and the load consists solely of arcs, the arcs 

 could alter the character of the wave-form. If the arc is re- 

 placed by a resistance, the wave-form is of the same type as is 

 obtained for the E.M.F. of the machine on open circuit. 

 Philadelphia. 

 Academy of Natural Sciences, April 7. — Mr. J. Willcox 

 described the process of obtaining quartz from the OrLskany 

 sandstone of Pennsylvania to be used in the manufacture of 

 glass. — Mr. G. Vaux, jun., called attention to recent additions 

 to the William S. Vaux collection, which included superb 

 crystals of calcite from the Joplin region, Missouri. They occur 

 in caves opened for the working of lead and zinc. The several 

 mines are characterised by distinct forms of the mineral. The 

 sphalerite, which is largely present, is being deposited at the 

 present time, the handles of shovels and picks left in the mines 

 being found covered with crystals. — Mr. Theodore D. Rand 

 described a fine collection of polished serpentines presented by 

 him to the Academy from numerous localities in South-eastern 

 Pennsylvania. They belong to two groups : one bordering the 

 ancient gneiss, the other and the more recent occurring in the 

 mica schists and gneisses. The former are altered igneous rocks, 

 either crysolitic or pyroxenic, the chief material being Enstatite. 

 — Dr. Bascom reported the microscopic examination of thin sec- 

 tions of serpentine from the Black Rocks of Lower Merion. — It 

 was announced that Mr. C«. Frederic Russell, accomjjanied by 

 Dr. Juelal and a taxidermist, had started from Cieorgetown, 

 British Guiana, March li,on a collecting tour in the interior 

 for the benefit of the Academy. 



NO. 1383 VOL. 53] 



