22 Description of a new Compensation Pendulum, 

 their merits as critics, by contrasting their lucubrations with 

 the sublime discoveries of sir Isaac Newton ? Or has the 

 science of optics a more intimate alliance with chemistry 

 than with criticism ? When an individual arrogantly invites 

 comparisons, he deserves to be humbled ; but to drag an un- 

 assuming, unoffending labourer in any science, into contrast 

 with a luminary in another science, for the purpose of degra- 

 dation, is, to say the least of it, an act of wanton cruelty, 

 and savours more of envy than of sound criticism. Edit. 



III. Description of a new Compensation Pendulum. By 

 Mr. H. Ward, of Blandford, Dorsetshire *. 



Reference to the Engraving. Plate II, 

 Fig. 2, 3, 4, 5. 



-T ig. 2. is a side view of the pendulum rod when to- 

 gether, khii are two flat rods or bars of iron, about an 

 eighth of an inch thick, k k is a bar of zinc interposed be- 

 tween them, and is nearly a quarter of an inch thick. The 

 corners of the iron bars are bevelled off, that they may meet 

 with less resistance from the air ; and it likewise gives them 

 a much lighter appearance. These bars are kept together 

 by means of three screws 111, which pass through oblong 

 holes in h h and k k, and screw into i i. The bar h h is con- 

 nected to the one k k by the screw m, which I call the ad- 

 justing screw. This screw is tapped into h h, and passes 

 barely through kk; but that part of the screw which enters 

 k k has its threads turned off. The bar i i has a shoulder at 

 its upper end turned at right angles, and bears at the top of 

 the zinc bar k k, and is supported by it. It is necessary to 

 have several holes for the screw m in order to adjust the 

 compensation. See Fig. 1, 6. — Fig. 3, 4, 5. are a side 

 view of each bar separately. Fig. 6. shows the flat side of 

 the zinc bar. Fig. 1. is a front view of the pendulum-rod 

 when screwed together. The letters have the same reference 

 to the different figures. 



* From Transactions of the Society for the Encouragement of Arts, Manu- 

 factures, and Commerce, for 1807; but with corrections communicated by 



the author The silver medal of the Society was voted to Mr. Ward for 



this invention. 



Now 



