100 Mr Meikle on a proposed Improvement 



rocks above. I did not meet with the Viola lutea. I visited tlie hills in Sep- 

 tember : at the time of flowering it is likely it might be found ; the V. trico- 

 lor was flowering in abundance. To offer a list of the plants growing on the 

 hills themselves, or at their base, is needless, as it would embrace half the 

 compendium of British plants. I shall allude only to the rarer ones. The 

 most remarkable, and those which seem to have claimed these hills as their 

 own, are the Digitalis purpurea, of which a white variety is often met with, 

 and the Hyoscyamus niger, most abundant on the North Hill, and above East- 

 nor Wood a varisty occurs with five racemes : whenever the soil has been ac- 

 cidentally disturbed, it sends forth its leaves, and, like the Digitalis, abounds 

 most in those stony spots which the Motacilla cenanthe has marked out as his 

 abode. In the moist places towards the base of the range, Marchantia poly- 

 morpha, Serapias longifolia. Orchis bifolia, O. conopsea, O. ustulata, Ranunculus 

 lingua, Myosotis minimum, R. pa'i-vijiorus, Colchicum autumnale. Polygonum minus, 

 P. aviculare, P. viviparicm, Scirpus acicularis, Satyrium, viride. Campanula rotun- 

 difolia, patula, latifolia, &c. In the woods, Galanthus nivalis, Chlora perfoliata, 

 Aquilegia vulgaris, Acer campestris and pseudo-platanus, &c. &c. The brambles 

 and briars are covered with the Clematis and Tamus communis. On the hills, 

 Arenaria tenuifolia, Drosera rotundifolia, Fumaria claviculata, Cistus helianthe^ 

 mum, C. polyfolius, Helleborus viridis, Hypericum androscemum, &c. On the 

 granite rocks, were found the Sedum album, and Cotyledon umbilicus. On the 

 limestone rocks the Potentilla verna flowers prettily; and the following list of 

 the Lichens which I obtained, is a pretty accurate list of those which are to be 

 found on this range : Lichen geographicus, L. islandicus, L. parellus, L. physodes, 

 L. plicatus, L. pustulatus, L. rangiferinus, L. scrobiculus, and L. scrobiculatus. 



1. Proposed Improvement in the Theory of Sounds and in the 

 mode of Measuring its Velocity. 2. On the Theory of the 

 Variation of the Barometer. By H. Meikle, Esq. Com- 

 municated by the Author. 



A HE propagation of sound through elastic fluids, was first 

 considered by Sir Isaac Newton ; but his investigations led to a 

 result considerably short of 1142 feet, the experimental velocity 

 in a second, so long received in this country, and which, owing 

 to some inaccuracy, was far above the truth ; for the mean ve- 

 locity is now found by experiment to be only about 1100 feet. 

 Newton's result still lay much below the latter number ; but those 

 who have investigated the velocity from the same data, have ac- 

 quiesced in his conclusion. It was not known in Newton''s days, 

 that, when air undergoes a change of volume, it at same time 

 changes its capacity for heat, becoming warmer by compression, 



