OF ARTS AND SCIENCES. 19 



Platinum. — As far as we can learn, no evidence lias hitherto been 

 offered to show the occurrence of this metal in the solar atmosphere. 

 We were somewhat surprised, therefore, upon meeting with coinci- 

 dences. Between 4250 and 4950 we find 64 lines of platinum, six- 

 teen of which agree with solar lines. The latter are at the following 

 places : — 



4291.10 4481.85 



4392.00 (Thalen 4389.4) 4552.80 (Thalen 4551.8) 



4430.40 4560.30 



4435.20 4580.80 



4440.70 4852.90 (Thalen 4851.5) 



4445.75 (Thalen 4442.0) 4857.70 



4448.05 4899.00 



4455.00 4932.40 



We have taken all possible care to make this statement accurate, 

 and to admit no lines about which there seemed to be any question. 

 There are seven other lines not included in the list, the probability of 

 agreement of which is at least as good as that upon which potassium 

 is admitted. 



In all these experiments everything has been done to bring out and 

 show upon the photograph as much as possible. The lamp, con- 

 structed for the purpose and fed by a powerful dynamo, gave an 

 arc from a half to three fourths of an inch loner, and burned with 

 a long flame and so intense a heat that it could be worked for but 

 a few minutes at a time. Any one who has carried out a series of 

 experiments like this is alone competent to appreciate the great labor 

 and the endless difficulties and perplexities that attend them. 



Our thanks are especially due to Dr. Wolcott Gibbs for his 

 hearty encouragement, and for the use of valuable apparatus and 

 chemicals. 



