from Dumbarton are well known, in which analcime and prehnite are so conjoined, that it is generally impossible to say where one terminates and the other commences; but it would be endless to adduce all the examples of this kind, with which I am acquainted, and in which assuredly no transition can be suspected. Why should not the specimen of bardiglione, mentioned by the Abbé Haüy, be classed with these?
I have applied to this substance the above denomination, which recalls that already appropriated to one of its varieties by the Italians, and which of itself has no other signification; conformably to my opinion, that every species, to whatever branch of natural history it belongs, should have a peculiar name allotted to it; a name that, from its nature, ought to be invariable, like the species it is intended to designate; while explanatory phrases, which are a natural exhibition of the state of the science at the time they are formed, must necessarily follow its course, and change with it. It is true the name of Anhydrite has already been given to this substance: but the intention of this name is to express the absence of water in its composition; and as on this account it may agree with a very great number of other mineral substances, which are in the same situation, it becomes therefore a general term, and not a proper name. This will always be the case, while authors endeavour to give mineral substances a significant name; it being sometimes taken from a quality supposed to be perceived for the first time, but soon after shewing itself to be too general to designate one substance. in particular; and being at other times founded on a quality merely peculiar to the individual, or accidental and of which a great number