708 



SCIENCE 



[N. S. Vol. XXXVIII. No. 985 



now generally considered most effective. The 

 horizontal board -was hexagonal, six feet in 

 diameter (radius of the inscribed circle), sur- 

 rounded by a vertical rim which extended six 

 inches below the plane of the board. It was 

 supported at a height of a little more than two 

 feet above the head of the speaker. 



After a considerable number of preliminary 

 trials, all of the same general character, a 

 final comparative test was conducted as fol- 

 lows: 



Eight hearers assisted, distributed through 

 seats G, N, U, and the gallery. The speaker 

 stood in his appointed place, and read a list of 

 disconnected words from a spelling book, while 

 each hearer noted down the number of words 

 not understood. The speaker then read a 

 short passage, of a known number of words, 

 from the chosen oration, the hearers noting, as 

 before, the words missed. The hearers then 

 changed places, those in G going to N, those 

 in N to f7, etc., and again a list of words was 

 read from the spelling book, and a passage from 

 the oration. This was continued until each of 

 the eight hearers had sat in each of the as- 

 signed seats. The number of words under- 

 stood by a hearer in a given seat in any one 

 trial was expressed as a percentage of the 

 whole number read during that trial. The 

 average of the percentage numbers for all the 

 eight hearers was taken as the acoustic effi- 

 ciency of the seat. 



Two such sets of experiments were made, 

 the speaker standing, in experiment I., at 

 the front edge of the chancel floor, in the 

 middle; in experiment II., in the pulpit, under 

 the sounding board. 



Gallery 



Unconnected words : 

 I. On tjhancel floor.. 



II. In pulpit 



Connected discourse : 

 I. On chancel floor.. 

 II. In pulpit 



The two sets of experiments should be 

 strictly comparable, as they were made in the 

 same afternoon, and involved the same speak- 

 ers and the same hearers in the same places. 

 The results follow. The figures represent in 



each case the average percentage of words 

 understood by the eight hearers. 



These results seem to show that the bene- 

 ficial effect of a sounding board in this place 

 is very small or inappreciable. This is per- 

 haps no more than was to be expected, for it is 

 difficult to give any reason why a sounding 

 board should greatly diminish the reverbera- 

 tion in an auditorium. 



The experiments described afforded a con- 

 siderable amount of other information, with 

 regard to the most advantageous pitch of the 

 speaker's voice, the rate of speaking, and 

 other phases of the subject, but as such results 

 would apply only to the auditorium studied 

 and would have no general value, they have 

 not been discussed. 



Frank P. Whitman 



Western Reserve University, 

 October 25, 1913 



THE AMEMICAN CHEMICAL SOCIETY 



ROCHESTER MEETING 



III 



DIVISION OP PHARMACEUTICAL CHEMISTRY 



B. L. Murray, Chairman 



F. E, Elred, Secretary 



B. L. Murray: Chairman's Address. Legislation 



Affecting Pharmaceutical Chemistry. 

 A. W. Bender: The Determination of Mercv/ric 



Iodide in Tablets. 



Several methods and modifications of methods 

 were tried on the tablets with very unsatisfactory 

 results. The difficulty experienced was due in a 

 large measure to the other ingredients in the 

 tablets, namely, terra alba, potato starch, talc and 

 gelatine. The method which was finally found to 

 give satisfactory results is a modification of the 

 sulphide method. 



The method consists in dissolving the mercuric 

 iodide by the use of HCl and KClOs, filtering, 

 making the filtrate alkaline with ammonia, and 

 precipitating with H^S. 



The method was also found to be useful for the 

 assay of mercuric iodide and oleate of mercury. 

 J. B. Williams: Tlie Insecticidal Value of Fluid 



Extract of Larkspur Seed. 



Fluid extracts of larkspur seed on the market at 

 the present time show great variation in physical, 

 chemical and insecticidal properties. 



Fluid extracts obtained by extracting the seed 



