466 Proceedings of Societies : [Oct. 



centre ; the under surface is of a gray colour, and is not hairy ; if wet- 

 ted it does not turn of an orange colour ; its edges are flat and thin. 



" The Bad has no mealy white powder on its surface ; its under 

 side is hairy, and blacker than the good ; its edges are usually more 

 or less knobbed, and on being wetted it generally becomes of an orange 

 colour. 



" No. 24, contains a mixed sample of good and bad, which has been 

 wetted with water. 



" The useless Mosses greatly outnumber the useful, and vary from 

 each other, in some instances, by such slight shades of difference, 

 that the above specimens of them can serve little more than to call 

 minute attention to the subject. A test for the discovery of colour is 

 therefore necessary. 



" Test. — Take liquor ammoniee, very much diluted with water, 

 but strong enough to retain a powerfully-pungent smell — half-fill a 

 phial bottle with the same, then add of the Lichen (being broken up 

 to a convenient size), so much as will lightly fill up the liquor, so 

 that the whole may be readily stirred about. Care must be taken to 

 leave at least one-third of the bottle for air. The bottle must be kept 

 corked, but be frequently opened, and the contents stirred with a small 

 stick. The colour will begin to exhibit itself in a few hours, and the 

 more rapidly in proportion to the warmth of the place in which it is 

 kept; but the heat should not exceed 130° Parenh. Apiece of white 

 silk placed near the surface of the fluid will show the colour before it 

 would otherwise be perceptible. This test will only serve to show 

 where colour exists, but will not develop it to its fullest extent. 



" Localities. — The good sorts are generally found in rocky or 

 stony districts, or where dry stone walls abound ; in the neighbour- 

 hood of the sea, — or if distant from the sea, in places exposed to sea 

 breezes. The more valuable are met with in volcanic islands. My 

 own experience has been principally in the Canaries, where I find 

 the more arid the situation, the better the quality of the Lichens. 

 "When the land is high and humid, the useless sorts alone are met with. 

 In dry places near the sea, there are only the good sorts and there 

 is generally a belt between the two, in which both good and bad are 

 found on the same stones, and not unfrequently overrunning each 

 other. 



" There is with the samples a small bottle of ammoniacal liquor, of 



