Progress of Invention. 78 



other material ; and a crystal ornament, cut in facets like a diamond, 

 and drilled through, which measures in its horizontal diameter 

 nearly two inches, and in its transverse diameter not quite an inch 

 and a half. There was also found in this grave the claw of an 

 animal, pierced through, evidently for suspension on the person. 



T. W. 

 The Rev. W. Kilbride, vicar of Aran, and G. H. Kinahan r 

 F.R.G.S.L, of the Geological Survey of Ireland, have recently 

 discovered the sites of two ancient settlements on the Islands of Aran, 

 County Galway. The settlement on Inish More, the largest of the 

 islands, consists of eight Cloghauns, or dry stone cells with " beehive 

 roofs ; " fifteen Cnocans, or dry stone beehive cells covered with 

 clay ; four Fosleac, or cells built of and roofed with flags ; four 

 Ointigh, or dry stone cells that had not beehive roofs; two Doons r 

 and one Cashel. The settlement on Inish-Maan, the centre island, 

 consists of thirteen Cnocans and Cloghauns and one small Doon. 



PROGRESS OF INVENTION. 



New Regulator op Velocity. — Motion is rarely obtained con- 

 tinuously from any source in such a state of uniformity, as the 

 purpose for which it is destined requires. Hence ingenuity has 

 devised a number of contrivances which, if they, in no case render 

 the motion perfectly uniform, in most they regulate it with sufficient 

 precision for the attainment of the intended object. The regulators- 

 used with chronometrical instruments give riseto periodica 1 alter- 

 nations of rest and motion ; which though objectionable from the 

 necessity of alternately destroying motion and overcoming inertia, 

 is found to comply sufficiently with the conditions which are to be 

 fulfilled. Such regulators, it is obvious, would be inapplicable 

 where interruption of motion is inadmissible ; and hence regulators, 

 founded on different principles, are then indispensable. It might be 

 supposed that friction would answer the purpose of absorbing the 

 excess of motion which would produce augmented velocity ; but 

 such is not the case, as the circumstances which give rise to friction 

 are so various, and so little under control ; and hence it is never 

 used as a means of regulation, when great exactness is required. 

 The resistance of the air affords a more suitable mode of regulation. 

 As the resistance offered by the air to any surface moving in it, is 

 proportionable to the square of the velocity, it is clear that the re- 

 sistance increases much more rapidly than the velocity ; and that the 

 velocity of any body having a large surface will be but little affected 

 by slight variations in the power. It will, however, be affected ; and 

 hence absolutely uniform motion is unattainable when the regulator 

 consists of revolving vanes. The happy idea occurred to M. Leon 

 Foucault, of combining with the principle of revolving vanes that of 

 the centrifugal governor used with the steam engine, etc. : and the 

 result is a regulator of great simplicity, which affords a motion 



