176 



SCIENCE. 



[N. S. Vol. XVII. No. 422. 



cornet, Fremeh horn, bombardino, saxo- 

 phone, clarinet, oboe, voice and violin. The 

 mechanical efficiency is generally between 

 one thoasandth and one hundredth. An 

 idea of the magnitudes involved can be 

 got from the statement that the sound 

 emitted from five to ten million cornets 

 would equal a horse-power. 



The Damped Ballistic Galvanometer: 0. M. 



Stewart, University of Missouri. 



It is usually assumed that a ballistic 

 galvanometer if well damped does not give 

 deflections strictly proportional to the 

 quantity of electricity discharged through 

 it. It has, however, been found experi- 

 mentally that such an error if any is very 

 small. The theory of the ballistic galva- 

 nometer is developed for the two general 

 cases: (1) periodic vibrations, and (2) 

 aperiodic vibrations. In both cases the de- 

 flection is strictly propoi'tional to the 

 quantity discharged through it. Efliect of 

 the damping on the sensibility of the galva- 

 nometer is discussed. 



On the Electrical Conductivity of Solu- 

 tions in Amyl Amine: Louis Kahlen- 

 BERG, University of Wisconsin. 

 The dielectric constant of amyl amine is 

 4.50, while that of chloroform is 3.95 and 

 that of ether is 4.37. Chloroform solu- 

 tions that conduct electricity appreciably 

 are unknown; ethereal solutions are also 

 extremely poor electrolytes. Ferric chlo- 

 ride dissolved in chloroform or ether yields 

 solutions that are practically insulators. It 

 was, therefore, of interest to determine the 

 conductivity of solutions in amyl amine. 

 The amyl amine was dried with fused caus- 

 tic potash and redistilled. Its speciflc con- 

 ductivity was less than 8.2 X 10~^. Cad- 

 miiun iodide, silver nitrate and ferric chlo- 

 ride are soluble in amyl amine, and the so- 

 lutions are electrolytes. Their conductivity 

 was measured by means of the Kohlrausch 



method. In the case of cadmium solution 

 the molecular conductivity first increases 

 with the dilution and then it increases on 

 further dilution, the maximum (0.542) oc- 

 curring when one gram molecule is con- 

 tained in about one and one tenth liters. 

 The mol. cond. is almost nil when one 

 gram mol. is present in six liters. Silver 

 nitrate solutions act similarly, the maxi- 

 mum (1.48) occurring when one gram mol. 

 is present in about one and two tenths 

 liters. The cond. is exceedingly low 

 when one gram mol. is contained in 31 

 liters. In the case of ferric chloride the 

 mol. cond. decreased continuously (from 

 0.217 at u = 5.021) as the solution became 

 more dilute, rapidly dwindling to a very 

 small value at about the same concentra- 

 tion as the AgNOg solutions. The con- 

 ductivities of solutions of these three salts 

 at higher dilutions than those mentioned 

 were found to be practically negligible. 

 The results show that, contrary to what 

 one would expect according to the Nernst- 

 Thomson rule, amyl amine yields solutions 

 that conduct well enough readily to admit 

 of measurement. Again the change of the 

 mol. cond. as the solutions are diluted is 

 such that it can not be harmonized with 

 the theory of electrolytic dissociation. The 

 fact that the mol. cond. dwindles to prac- 

 tically nothing in solutions of the concen- 

 tration above mentioned is particularly in- 

 teresting. Potassium iodide and sodium 

 oleate are insoluble in amyl amine. Cop- 

 per oleate is soluble, but the solutions con- 

 duct no better than the pure solvent. 



On the Thermal Conductivity of Glass: 

 li. W. Springsteen, Case School of Ap- 

 plied Science. 



;8'o»ie Relations between Science and the 

 Patent System: Charles K. Wead, U. S. 

 Patent Office. - 

 This informal paper will call to the at- 



