Miscellaneous. 317 



the form of this plant occurring on the higher Vosges on granitic 

 and syenitic soils (described by Spach as Viola elegans) ; its stem 

 being more procumbent and repeatedly branched at the base, and 

 the flowers being generally smaller. I will not, however, express 

 any further opinion as to whether this violet may or may not be a 

 distinct species, for the violets of the same group as V, tricolor pre- 

 sent so many difficulties to systematic botanists in consequence of 

 their extraordinary variability, that it is difficult to find the middle 

 course between the union of them all under one name, and the 

 establishment of a multitude of species. Many other plants grow 

 in company with the Viola calaminaria, which, although in this 

 district peculiar to the calamine hills, nevertheless grow in other 

 localities in soil free from calamine. 



1'he colour of the flowers of the Viola lutea of the Alps and 

 Vosges varies from the darkest violet to the purest yellow, whilst 

 the flowers of V. calaminaria, at least in the neighbourhood of Aix, 

 are almost always yellow. On the borders of the calamine district 

 specimens are met with here and there with pale violet, or bluish, or 

 mixed blue and yellow flowers, which have been regarded by Kalten- 

 bach as hybrids between this plant and the F. tricolor, which cer- 

 tainly occur on cultivated land in the neighbourhood. But I have 

 also seen a specimen of the true V, calaminaria from the calamine 

 region of Westphalia which is of a dark violet colour. The plant 

 when cultivated in gardens is said to change and become like the 

 common V. tricolor. 



The connexion between the occurrence of the V. calaminaria and 

 the presence of calamine in the soil, which is so constant that even 

 mining experiments have been undertaken with good results from 

 the indications furnished by this plant, induced me, when in Aix, to 

 urge M. Victor Monheim of that place, to examine the plant 

 especially with reference to its containing zinc. He afterwards 

 sent me the following account of a chemical investigation of the 

 plant, performed in his laboratory and under his eye, by M. F. Bel- 

 lingrodt, wliich I give in the latter gentleman's own words : — 



"The plants, some of which were still in flower, were collected 

 in the month of October on the Altenberg and in the immediate 

 neighbourhood of its large zinc works. To get rid of adhering 

 earth completely, the fresh, uncut herbage with the roots was 

 washed with water, until, when macerated for sixteen or eighteen 

 hours with water containing muriatic acid, it gave no inorganic 

 matter to the dilute acid. The whole was then finely chopped and 

 digested on the vapour- bath for twelve hours with water and mu- 

 riatic acid; the vegetable matter was separated from the extract, 

 and this treated with chlorate of potash. The addition of an excess 

 of ammonia to the decolorized extract, now produced a precipitation 

 of alumina, organic substances, and partially of the iron. 



" The precipitate produced in the filtrate by sulphuret of ammo- 

 nium was dissolved in muriatic acid, oxidized by nitric acid, and 

 the iron then completely separated by ammonia- A portion of the 



