52 Royal Society : — - 



The author next proceeds to examine the law under which thia 

 resistance varies ; and considering the total resistance in the solid 

 beam to be composed of two resistances, one being constant and 

 due to the tensile strength, and the other variable and depending on 

 the depth of the metal in connexion with its deflection, the experi- 

 ments indicate that the resistance to flexure varies, throughout all 

 the girders, directly as the amount of deflection into the depth of 

 the metal. 



The paper concludes by pointing out the important amount of 

 this resistance, tlie operation of which has been hitherto unknown, 

 and which in cast iron exceeds the tensile strength of the metal, and 

 shows that comparisons of the strength of different forms of section, 

 based on the existing theory, which assumes the resistance at the 

 outer fibre to be constant and equal to the tensile strength of the 

 metal, must be entirely fallacious. 



The paper is accompanied by full details of all the experiments, 

 and the measurements for determining the position of the neutral 

 axis. 



"On the Metallic and some other Oxides, in relation to Catalytic 

 Phaenomena." By the Rev. J. Eyre Ashby. 



I purpose to detail some experiments on the metallic (and a few 

 other) oxides, made with a view to ascertain their powers to produce 

 and maintain, catalytically, the combustion of various gases and va- 

 pours ; and to annex such considerations as appear to be suggested 

 by the facts. By catalysis I understand the operation of one body 

 upon another, under favourable circumstances, whereby the second 

 body is resolved into new chemical combinations, while the first 

 (whatever may happen during the process) remains finally un- 

 changed. This must be taken as not including explosion by per- 

 cussion, in which the change takes place owing to the external 

 application of dynamic force. 



The apparatus for experimenting comprehends a variety of shal- 

 low capsules ; wire-gauze, of iron, copper, and brass, of different de- 

 grees of fineness, cut into discs a little larger than the vessels on 

 which they are to be su])eriniposed ; a spirit-lamp with large wick ; 

 a pair of pliers, and a few rings of wire to support the gauze, if 

 necessary, while heating it in the sjiirit flame. I'he method of pro- 

 cedure is simple : the watch-glass, or capsule, is nearly filled with 

 the liquid whose vapour is to be tried ; on a wire-gauze disc is 

 spread the oxide whose powers as a catalyser are to be tested, and 

 this being warmed (more or less) over the lamp, is set down upon 

 the upper rim of the capsule. Sometimes it is necessary to heat a 

 layer of the oxide in the middle of a small combustion-tube, and 

 pass over it the gas, or mixture of gases. 



I tried the following substances with pyroxylic spirit (hydrated 

 oxide of methyle) and alcohol separately. 



1. CoO appeared to possess the power in some degree, but per- 

 haps the specimen was in too dense agglomeration, which is not 

 essentially reduced by trituration. 



2. Co^, O.^ maintained the catalytic combustion very well. 



