SPECIFIC GRAVITY OF LIGHT, \^§ 



VIII. 



A Method of finding the specific Gravity of Light from Ana* 

 logy; and the undulalory St/stem defended by an Expert* 

 mod on inflected Light. In a Letter from Mr* Richard 

 Winter. 



To Mr. NICHOLSON. 



Dear Sir, Wliithy, Jan. 8th, 1S03. 



JL HE undulatory system of light had until within very Undulatory 

 lately become exploded by the extraordinary abilities of New- system of UgUt 

 ton, and his great exertions in favour of the emanative sys- a ^| n to'c^iff* 

 tern ; bat no name, however great, should prevent inquiry attention, 

 after truth and extension of science, so naturally allied to 

 the civilization and happiness of mankind. It is, I believe, 

 generally allowed, that few discoveries have been made by 

 pursuing a beaten path ; it is on this account that so few im» 

 provements have been made in the theory of light since the 

 time of Sir Isaac Newton. Dr. Young's experiments, and 

 reasoning from facts, in favour of the undulatory motion of 

 light, are deserving of impartial attention. 



The great influence of light on vegetables and animals is Light has g*aai 

 ascertained, from the want of colour in both when deprived influence on 

 thereof; and the vigour, odour, and density of tropical anhnals- 

 plants, and the ferocity of animals indigenous to those cli-e 

 mates. Its consequences in the arts and manufactures are ln arts a ^j ma ^ 

 very considerable, in its various combinations with the ele- nufactures 5 

 mentary bodies. Its effect also upon man is acknowledged on m an* 

 and felt by all nations, so as to contribute a principal cha-> 

 racteristic (viz. that of colour). 



The physical phenomena arising therefrom display a wide and t « 



field for the investigation of the natural philosopher, in the phenomena, 

 production and change of colours — the formation of the rain- 

 bow, parhelia, haloes, &c. 



It has baffled the ingenuity of man to determine its den^ It:} j cas j ty Bo6 

 sity by mechanical means. Michell attempted to find its e «y fe.aiOTN 



momentum 



