The Rev. S. Haughton on Hanging. 23 



tion exerted between two pieces of floating ice. It is to be borne 

 in mind that, when in water, much more delicate ice-bridges suf- 

 fice to connect two pieces of ice than when they are surrounded 

 by air, where it is difficult to render the equilibrium so perfect as 

 in water. 



That radiant heat passing through ice melts the substance at 

 points deep in the interior may be explained by assuming that 

 at such places the ice-crystals have so crowded upon each other 

 as to cause a pressure. If the water produced at such places be 

 refrozen, the local pressure will be restored, and a new stream of 

 heat will effect liquefaction at the same places, even when no free 

 surface exists there. 



According to Professor Tyndall's theory, the latent heat ren- 

 dered free when two pieces of ice freeze together is conducted 

 away through the adjacent ice. And as the difference between 

 the freezing-points of the interior and superficial ice is certainly 

 very small, the heat rendered sensible must diffuse itself through 

 a comparatively large mass of ice if internal liquefaction is to be 

 avoided. In view of the low conductive power of ice, and the 

 extremely small differences of temperature, this seems to me im- 

 probable in cases where by a strong pressure, even by the stroke 

 of a hammer, pieces of ice are welded together. I confess, how- 

 ever, that the time necessary for conducting away the heat can- 

 not be subjected to exact calculation, and that therefore the 

 question under discussion cannot yet be regarded as decided. 

 For my own part I gave the theory of Mr. James Thomson the 

 preference, because it bases itself exclusively upon w T ell-known 

 facts. 



II. Helmholtz. 



IV. On Hanging, considered from a Mechanical and Physiolo- 

 gical point of view. By the Rev. Samuel Haughton, M.D., 

 F.R.S., Fellow of Trinity College, Dublin*. 



HANGING, as a mode of public execution of criminals, must 

 be regarded as to a great extent an Anglo-Saxon mode 

 of execution; and although occasionally practised by the nations 

 of antiquity, it seems among them to have been used chiefly by 

 suicides, or in cases in which especial ignominy was intended 

 to be attached to the criminal. 



Among the Hebrews, the national punishment was unques- 

 tionably that of stoning to death by stones thrown with the 

 hand ; and it is clear, from many passages in the Old Testa- 



Communicated by the Author. 



