246 PHILOSOPHICAL TRANSACTIONS. [anNO 1758. 



It was followed by a quivering of the earth ; and after this a wind issued out of 

 the hole, which agitated the plants round about. He watched to see whether 

 the motion extended to any distance; but was sensible it did not reach above 3 

 or 4 paces from the hole, and that no motion was perceived farther off. 



He further observed, that this phenomenon never happens till after the 7 th 

 wave rolls in ; for it is a common thing in this country to find the sea appear 

 calm for some time, and then produce 7 waves, which break on the coast one 

 after another: the first is not very considerable: the 2d is somewhat stronger; 

 and thus they go on increasing to the 7 th, after which the sea grows calm again, 

 and retires. This phenomenon of the 7 waves is observed by navigators with 

 great attention, especially at low water, to be the better able to go in or come 

 out the very time that the sea grows quiet. These 7 waves successively fill the 

 caverns, which are all along the coast; and when the 7th comes to open itself, 

 the air at the bottom of the caverns being greatly compressed, acted by its elas- 

 ticity, and immediately made those fountains and gushing-s abovementioned ; and 

 the water continuing in the caverns, up to the very place of the hole, began to 

 produce that dull noise, caused the emotion or earthquake, and finished with 

 the violent wind forced up through the hole; after which the water retired into 

 the sea, and having no further impelling cause, on account of the waves, ren- 

 dered every thing quiet again. 



XC. A Catalogue of the Fifty Plants from Chelsea Garden, presented to the 

 Royal Society, by the Company of Apothecaries for the Year 1757, Pursuant 

 to the Direction of Sir Hans Sloane, Bart. By John fFilmer, M. D. p. 648. 



[This is the 36th annual presentation of this kind, completing to the number 

 of 1800 different plants.] 



XCL An Historical Memoir on a Genus of Plants called Lichen, by Micheli, 

 Haller, and Linneus ; and comprehended by Dillenius under the terms Usnea, 

 Coralloides, and Lichenoides, tending principally to Illustrate their several 

 Uses. Communicated by Wm. JVatson, M. D., F. R. S. p. 652. 



The whole class of mosses was but very little noticed by the revivers of botany 

 in the l6th century: they indeed took some pains to distinguish the particular 

 sj^ecies mentioned by the ancients, but disregarded almost all the rest. Modern 

 botanists however suppose, that they were but little successful in general in their 

 application of the ancient names to plants: nor is a failure in such attempts to 

 be wondered at, considering the too great conciseness, and frequent obscurity of 

 their descriptions. In the class of mosses, as in many others, the accounts 

 transmitted to us are little more than a scene of uncertainty and confusion. It 



