On FossilCoXixmiiQS in the Carboniferous Strata near Wigan. 259 



detected at once by the fine orange-red colour which the re- 

 agent assumes when it is heated in contact with that mineral. 



A vanadiate gives a dark colour, but possessing less of the 

 red shade than the niolybdate. The liquor filtered from the 

 sulphuret of lead containing the vanadium in solution has a 

 green colour, becoming blue by the addition of hydrochloric 

 acid. Hence it appears that arsenic dissolved in bisulphohy- 

 dret of ammonia does not alter the colour of that reagent, while 

 the liquor gives a precipitate of orpiment by concentration. 

 Molybdenum and vanadium, on the other hand, render that 

 reagent I'eddish, and give brown precipitates by concentration. 

 The liquor filtered from the sulphuret of molybdenum is 

 colourless, or its hue is similar to that of the reagent, while 

 the liquor derived from the vanadium precipitate is green, 



I have succeeded in decomposing a sufficient amount of 

 these minerals for quantitative analysis by the preceding prp^ 

 cess when they have been carefully pounded and laevigated. 

 The process is particularly advantageous in the analysis of 

 molybdate of lead, where the use of nitric acid for dissolving 

 the mineral is objectionable in consequence of its tendency to 

 form the molybdate of molybdenum, and where hydrochloric 

 acid, by producing a chloride of lead, renders the employment 

 of an inconvenient quantity of water necessary. I have found 

 this process for testing very convenient where it was desirable 

 to use minute quantities of crystals, and where rapidity is an 

 object in view, as in examining a large collection of minerals 

 of the preceding description ; and I mention it for the sake of 

 those who may possess in their cabinets minerals of this nature 

 which they may desire to test, since it may be found a use- 

 ful adjunct to the blowpipe test. 



The bisulphohydret affords a simple distinguishing test 

 between metallic arsenic and antimony, when spots have been 

 received on porcelain by Marsh's process. Arsenic dissolves 

 in the reagent, and leaves a yellow stain by evaporation. An- 

 timony dissolves and leaves an orange stain. For this expe- 

 riment it is convenient to use the inside of the cover of a 

 porcelain crucible. 



X LI 1 1. 0}i Fossil CdXuxmies found standing in an erect position 

 in the Carboniferous Strata near Wigan, Lancashire. Bi/ E. 



W. BiNNEY*. 



THE fragmentary condition of the great bulk of fossil 

 plants found imbedded in the coal measures has led many 

 geologists to suppose that they had been drifted from adjoin- 



* Read before the Literary and Philosophical Society of Manchester, 

 July 6, 1847, and communicated by the Author. 



S2 



