160 Dr. A. Schuster on 



" proportions, of oil, salt, and earth ; and having by the 

 " analysis discovered those proportions they can, of those 

 " ingredients make sulphur. So we have only to suppose, 

 " that the parts of the sun's sulphur, separated by fire, 

 '* rise into his atmosphere, and there being freed from the 

 " immediate action of the fire, they collect into cloudy 

 " masses, and growing by degrees, too heavy to be longer 

 " supported, they descend to the sun, and are burnt over 

 " again. Hence the spots appearing on his face which are 

 " observed to diminish daily in size, their consuming edges 

 "being of particular brightness. 



"It is well we are not, as poor Galileo was, subject to 

 "the Inquisition for Philosophical Heresy. My whispers 

 " against the orthodox doctrine, in private letters, would be 

 " dangerous ; but your writing and printing would be highly 

 "criminal. As it is you must expect some censure, but one 

 " Heretic will surely excuse another. 



" I am heartily glad to hear more instances of the 

 " Poke-Weed, in the cure of that horrible evil to the human 

 " body, a Cancer. You will deserve highly of mankind for 

 "the communication. But I find in Boston they are at a 

 " loss to know the right plant, some asserting it is what they 

 " call Mechoachan, others other things. In one of their late 

 " papers it is publickly requested that a perfect description 

 " may be given of the plant, its places of growth, etc. I 

 " have mislaid the paper, or would send it to you. I 

 " thought you had described it pretty fully. 



" I am, Sir, etc., B. F." 



Travelling back from England to America Franklin 

 noticed in the lamps on board ship, in which the oil was 

 kept floating on a surface of water, a peculiar agitation at 

 the surface of separation between the oil and the water. On 

 his return home he made experiments on the subject, which 

 he describes : 



" Experiments" page 439. 



" Since my arrival in America, I have repeated the 

 " experiment frequently thus : I have put a pack-thread 



