Organic Matter found in Sulphureous Springs. 695 



Mr. Dillwyn adds, in a private communication with which he 

 has favoured me, that he has since found Conferva nivea abun- 

 dant in the hot springs about Aix la Chapelle, especially near 

 Frankenburg. 



I leave it to the many better judges of such matters, than 

 myself, that are to be found among the members of this So- 

 ciety, to pronounce, whether the body, whose appearances under 

 the microscope are faithfully depicted in the accompanying 

 drawing, approaches near enough to the characters of Dillwyn's 

 Conferva nivea to be regarded as the same, or as an allied spe- 

 cies. To this, the want of resemblance as to colour must not be 

 regarded an objection ; for the specimen I obtained at Digne, 

 which appeared under the microscope to be the same kind of 

 Oscillatoria as the one alluded to, was perfectly white; and 

 M. Longchamp, in his treatise on the Waters of Vichy, informs 

 us, that what he collected at Bareges was originally white, but 

 became green when kept for a few days*, so that the discre- 

 pancy as to colour ought not to be looked upon as establishing 

 a distinction of species. Neitlier will the difference of tem- 

 perature between the sulphureous water of Harrowgate and of 

 Greoulx be considered inconsistent with the notion of the same 

 Conferva growing in both, when we are reminded that it has 

 also been found by Mr. Dillwyn himself in the thermal waters 

 of Aix la Chapellet. 



At all events, it must be considered as a curious circumstance, 

 that springs, of whatever temperature, which give out sulphu- 



* This change also took place very rapidly in the C. nivea which I collected at 

 Croft in Yorkshire this autumn. 



t Dr. Hooker found close to the edge of the Geysers in Iceland, and within a few 

 inches of the boiling water, Conferva limosa, Dillw., a new species of Oscillatoria, 

 and the finest specimens of Jungermannia angulosa he ever saw. In water, also, of 

 a very great degree of heat, were, both abundant and luxurious, Conferva Jlavescens of 

 Roth, and a new species allied to C. rivularis. 



retted 



