468 JDr.A.W.Hofmann [April 11, 



Vereins zur BefSrderung des Gewerbjleisses in Preiissen — Verhandlungen, Nov. und 



Dec. 4to. 1861. 

 Vienna, Imperial Geological Institute — Jahrbuch, 1861-2. 8vo. 



Parnell, John, Esq. M.K.I.-- A Bottle excavated near Old London Wall, Basinghall- 

 Street. 



WEEKLY EVENING MEETING, 



Friday, April 11, 1862. 



John Peter Gassiot, Esq. F.R.S. Vice-President, in the Chair. 



Dr. A. W. HoFMANN, r.R.S. Pres. C.S. 



On Mauve and Magenta. 



The fact of the beautiful colouring matters known by these fanciful 

 terms being substances derived from coal, must, I presume, be familiar 

 to every one of you. But there may be many unacquainted with the 

 means by which this transformation is accomplished. It is to them that 

 I address myself this evening. 



Coal to become colour, has to pass through a series of stages of 

 transition, each of which claims our attention for a moment. Briefly 

 expressed, the aim of this address may be said to be, to show you the 

 way from coal to colour. Now let me at once tell you this way is 

 rather long ; we may have to travel over country rough and intri- 

 cate, and now and then to pass through territories which — I confess 

 it with an appeal to the ladies— may not, perhaps, be altogether 

 remarkable for their fragrance and sweetness. But on such occasions 

 we shall accelerate our steps, and, on the whole, I venture to hope that 

 we shall arrive at our journey's end without too much inconvenience. 



Colour is intimately associated with light ; without light there 

 is no colour. This remark applies in a double sense to the colours 

 derived from coal ; for it is to the introduction of gas-light for 

 illuminating our streets and houses, that we are indebted for the 

 acquisition of these colours. This statement may appear strange, for 

 nearly half a century has elapsed during which we have been in the 

 possession of gas, whilst the transformation of coal into colouring 

 matters has been achieved only recently under our own eyes. But you 

 will immediately appreciate the truth of my assertion, if I tell you that 

 these substances are obtained from a secondary product, generated in 

 the manufacture of gas, a product long used for a variety of purposes, 

 but which, only within the last few years, the researches of chemists 

 have proved to be an inexhaustible mine of wealth and interest. 



The starting-point then for the production of Mauve and Magenta, 



