TO THE MEMORY OF 
THE GREAT SIR ISAAC NEWTON 
I indulge an incUnatmi with much humility to dedicate 
this gift of Nature, as a part belonging to the foundation of 
light and colours, first laid by his penetrating genius ; presum- 
ing that collecting, measuring, and arranging them is a ne- 
cessary if not an. essential appendage. I had dedicated this 
more naturally, it might be thought, to the Honourable Presi- 
dent, Sir Joseph Banks, Bart, and to the Fellows of the Royal 
Society. The Dedication to the Memory of Sir Isaac Newton 
being admitted, the latter follows of course, as every thing re- 
lating to the philosophical scheynes of that great man naturally 
comes under their cognizance ; and they, like his heirs, under 
such circumstances I hope will he pleased to accept it, 
JAMES SOWERBY. 
London. 
