BLUE VESUVIAN LIMESTONE. loo From this analysis, it appears, that the vesuvian lime stone differs remarkably in composition from common compact limestone. In common compact limestone, 100 parts of lime are combined with at least 80 parts ot car bonic acid ; whereas in the vesuvian limestone, 100 parts of limestone are not combined with more than 50 parts of carbonic acid. Secondly, In common limestone, inde pendent of the water which adheres to it accidentally, as far as we know, there is no water of composition ; but in the vesuvian limestone, there are 11 parts of water of composition. Geographic Situation,. This remarkable limestone is found in loose masses amongst unaltered ejected minerals in the neighbourhood of Vesuvius. Observations. It is known to some collectors under the name Compact liluc Lava of Vesuvius; and is employed by artists, in their mosaic work, to represent the sky. Third
