6S felGHTIl REPORT — 1838. 



On Chemical Combitialions produced in virtue of tfie presence of oilier 

 bodies vjhich still remain. By Rev. T. Exi.e^, M.A. 



Mr. Exley points out in this paper the application of his theory to 

 the explanation of those cases in chemistry where powerful affinities 

 between bodies are brought into activity by means of other substances 

 which are present and continue to exercise the same energies. Berze- 

 lius attributes this to a peculiar force, which he calls catalytic, and Mr. 

 Exley taiies four examples to show how these phenomena receive an ex- 

 planation in conformity with his general view of atomic centres of force. 

 The first case is that of the combination of hydrogen and oxygen, 

 effected by the presence of clean platinum. " Since metals are simple 

 bodies and dense solids, the theory recognises their atoms as having 

 small spheres of repulsion, and those of ])latinum must be very small 

 because of the great density of the metal: hence, the atmosphere of 

 ethereal matter belonging to this metal is very dense, being more dense 

 as the square of the radius of the sphere of repulsion is less and as the 

 atomic weiglit is greater. For this reason the oxygen can approach ex- 

 tremely near to the atoms of platinum, and yet not combine with them 

 by reason of that dense atmosphere ; and the hydrogen being drawn 

 close on them the reunion in question occurs, the generated steam 

 escapes, heat is evolved, and the process advances till ignition is pro- 

 duced." 



The author examines in succession three other oases of supposed 

 peculiar actions, and explains them on the j^rinciples of his theory : 

 The conversion of starch into sugar by the action of a weak solu- 

 tion of sulphuric acid. 



The conversion of sugar into alcohol by the action of barm. 

 The conversion of alcoliol into ether by the action of sulphuric 

 acid. 



On an Improvement in the Manufacture of Iron, hy the AjypUcation of 

 Gas obtained from the decompositio)i of' Water. By John Samuel 

 Dawes, of Bromford cmd Oldhtry l7-onworks, near Birmingham. 



Mr. Dawes has attempted to obtain a heating effect approaching in 

 intensity to that which is produced by the oxy-hydrogen blow-pipe, but 

 upon a scale sufficiently large to be available in the smelting of iron. 



Hydrogen gas, in addition to its great inflammability, exhibits, when 

 applied to the above purpose, a purifying property in a high degi'ee, so 

 that the most sulphurous materials may be used with advantage, and 

 metal of good quality be produced. There can be little doubt (Mr. 

 Dawes thinks) as to the value of hydrogen thus applied ; the question 

 would rather be. Can the gas be obtained at a sufficiently cheap rate so 

 as to make the use of it profitable ? This, he thinks, may now be con- 

 fidently answei-ed in the affirmative. The method of proceeding is as 

 follows. Jets of steam are made to pass through red-hot cast-iron 

 pipes filled with small coke or charcoal ; (the riddlings from the coke 

 hearth answer the purpose, and are of little value ;) decomposition 



