On the Resistance of Glass Globes and Cylinders to Collapse. 535 



Comparison of these results with the composition of acetate of 

 silver gives as follows : — 



Calculated. Found. 



1. II. 



Per-centage of Silver 64-67 64-88 64-00 



which leaves no doubt as to the presence of acetic acid. 



Still further proof of the same was obtained by converting a little 

 of the acid into a soda-salt, and heating it with arsenious acid. 

 Abundance of kakodyle was evolved. 



In order to remove any doubt which might exist as to the 

 source of this acetic acid, and to show that it did not arise from 

 oxidation of the ether which accompanied the sodium-methyle, I 

 operated upon some of the original sample which had never been 

 exposed to carbonic acid, and which, as previously mentioned, had 

 been laid aside for comparison. 



I mixed it with a little mercury, distilled with excess of dilute 

 sulphuric acid, and digested the redistilled distillate with oxide of 

 silver, using the same samples of acid and of oxide of silver as in 

 the former experiment. 



The distillate neither smelt like acetic acid, nor yielded acetate of 

 silver on spontaneous evaporation to dryness in vacuo of its product 

 with oxide of silver. Neither could kakodyle be obtained on heating 

 its soda-residue with arsenious acid. 



From all which, it is evident that the acetic acid obtained must 

 have been the product of the action of carbonic acid. The following 

 conclusion is, therefore, established : — 



Dry carbonic acid is decomposed by sodium-methyle with evolution 

 of heat, and production of acetate of soda. 



Sodium-methyle. Acetate of soda. 



C,0,-HNaC,H3=C,0,C., 



Naj^^ 



I hope also to be able to present shortly an account of the action 

 of carbonic acid on one of the higher compounds of the alkali- 

 metals — most probably on potassium or sodium-amyle. 



May 12. — Sir Benjamin C. Brodie, Bart., President, in the Chair. 



The following communications were read : — 



"On the Resistance of Glass Globes and Cyhnders to collapse 

 from external pressure, and on the Tensile and Compressive Strength 

 of various kinds of Glass." By William Fairbairn, Esq., C.E., F.R.S., 

 and T. Tate, Esq., F.R.A.S. 



The researches contained in this paper are in contiimation of those 

 upon the Resistance of M'^rought-Iron Tubes to collapse, which 

 have been published in the 'Philosophical Transactions ' for 1858. 

 The results arrived at in those experiments were so important as 

 to suggest further inquiry under the same conditions of rupture 

 with other materials ; and glass was selected, not only as differing 

 widely in its jjhysical properties from wrought iron, and hence well 

 fitted to extend our knowledge of the laws of collapse, but because 



