430 Clironicles of Science. [July, 



of souhresaut, or bumping, during ebullition, wero next discussed, 

 and a variety of interesting facts were described. The action of 

 porous bodies in assisting distillation -was explained by their absorp- 

 tion of the vapour of the boiling liquids, which was subsequently 

 given out in never-ceasing jots ; and a number of obscure pheno- 

 mena in chemistry — such as the passive condition of iron, and the 

 slight action of sulphuric acid on pure and amalgamated zinc — were 

 explained by the doctrine of catharism, for which the lecturer 

 claimed the properties of a princij)le of nature — viz. generality 

 and breadth of application — a principle which was as yet new to 

 science. 



At the meeting on March 18, 1869, a paper was read by Mr. 

 Arthur Elliott, " On the Determination of Carbon in Cast Iron." 

 The author's method consists in treating pulverized iron borings 

 with solution of sulphate of copper, heating gently for ten minutes, 

 when the iron dissolves, and metallic copper separates, the carbon 

 remaining undissolved. Acid solution of chloride of copper is then 

 added, and the mixture heated nearly to the boiling point, until the 

 separated copper dissolves. The carbon is collected on a filter made 

 of combustion tube, and stopped first with broken glass, and then 

 loosely with ignited asbestos, and washed with boiling water till free 

 from cl derides. It is then converted into carbonic acid, and the 

 latter determined by oxidation with chromic acid. 



A paper was then read by Professor G. G. Stokes, F.E.S., " On 

 a Certain Eeaction of Quinine." The reaction is best observed by 

 diffused daylight entering a darkened room thi'ough a hole in the 

 shutter of about 4 or 5 inches square, or a packing-case may be 

 made to answer very well. The hole is covered with glass coloured 

 a deep violet by manganese. In front of it is placed a white por- 

 celain tablet ; a solution of quinine in very weak alcohol, or very 

 small fragments may be used. In some cases alcohol interferes 

 with the reaction. The phenomena exhibited by sulphuric and 

 hydrochloric acids wero as follows : — When a drop of the quinine 

 solution was touched by a rod dipped in dilute sulphuric acid, the 

 fluorescence of the quinine was instantly developed. With hydro- 

 chloric acid no apparent effect was produced, but hydrochloric acid 

 destroyed the effect of sul})huric acid ; and if a little suljihuric 

 acid were added to the drop containing only hydrochloric acid, no 

 effect was manifest. The author found that, on trying a variety of 

 acids, they ranged definitely into two classes, A and B — class A 

 developing fluorescence hke sulphuric acid, and class 13 destroying 

 it, like hydrochloric acid. The classification made by the quinine 

 reaction agrees almost exactly with the old distinction of ox-acids and 

 hydracids. The author had found, however, that hyposulphurous 

 acid, which is not usually ranked with the hydracids, ranged itself in 



