46 Dr Brewster on a new series of 



These tables were presented to the Committee by Mr W. 

 H. Wyatt, the editor of the Repertory of Arts. 



Average annual grant of Patents in the different reigns, 

 adopting the nearest whole number 



Charles II. 5 George I. 7 



James II. 4 George II. 8 



William and Mary. 8 George III. 61 



Anne. 9> George IV. 136 



We conclude this statement by an account of the number 

 of Patents obtained in England, France, and Austria, as pub- 

 lished in the " Polytechnische Jahrhiicher'''^ at Vienna, and 

 communicated to the Committee by Mr Hawkins. 



England. France. Austria. 



1821, 106 179 107 



1822, 115 



1823, 136 



1824, 180 



1825, 247 



1826, 130 



In six years, 914 



Yearly average. 152 



Average in England from 1818 to 1826, 188 



Plymouth, October 21, 1829. 



Art. VI. — On a new series of periodical colours produced 

 hy the grooved surfaces of metallic and transparent bodies. 

 By David Brewstee, LL. D. F. R. S. L. and E. * 



In the year 1822, when I received from Mr Barton some very 

 fine specimens of his Iris ornaments, I availed myself of the 

 opportunity of performing a series of experiments on the action 



• Read before the Royal Society of London, May 21, 1829, and slightly 

 abridged from the Phil. Trans. 1829, p. 301—316. 



