PROCEEDINGS OF THE AMERICAN ACADEMY 



4588.92 

 4589.40 

 4590.00 



4590.95 { 



4592.00 

 4592.95 

 4596.20 

 4601.37 

 4607.20 



4609.45 { 



4612.75 

 4614.05 

 4621.42 

 4630.73 

 4634.00 

 4638.90 

 4640.75 

 4641.90 

 4643.45 

 4645.40 

 4649.25 

 4651.02 

 4654.10 

 4654.85 

 4655.90 

 4658.05 

 4659.60 

 4665.70 

 4667.55 

 4671.65 

 4672.30 

 4673.30 



4674.95 j 



4676.40 

 4681.10 



Very faint. 



Strong, may 

 agree. 



Strong. 



a 



Very strong. 

 a 



Sharp, may 



agree. 



Faint. 



Strong, agrees. 



Strong. 



Very strong. 



Sharp. 



Strong. 



Rather faint. 



Fairly strong. 



Strong. 



Faint. 



Strong. 



Fairly strong. 



Faint. 

 u 



Faint band. 

 Very faint. 



u 



Faint. 



Very faint. 



Faint, may 



agree. 



Very faint. 



4682.40 

 4687.15 

 4688.80 

 4691.40 

 4694.15 

 4695.15 

 4696.70 

 4699.40 

 4700.40 

 4701.65 

 4703.02 

 4705.42 

 471020 

 4712.87 

 4719.92 

 4731.27 

 4733.95 

 4740.20 

 4744.20 

 4753.82 

 4760.07 

 4763.82 

 4771.82 

 4775.07 

 4782.62 

 4788.27 

 4791.32 

 4798.97 

 4800.82 

 4802.37 

 4808.94 

 4810.02 

 4811.92 

 4813.52 

 4816.60 

 4820 90 

 4822.12 

 4825.12 



Very faint. 



Strong. 

 Faint. 

 Very faint. 

 Broad and faint 

 Faint. 



Agrees. 

 Fairly strong. 



u 



Very faint. 



Sharp. 



Very strong. 



Very faint. 



Sharp, agrees. 



Very faint. 

 a 



Very strong. 

 Very faint. 

 Faint. 



Very strong. 

 Faint. 



Faint, may agree 



4842.00 

 4863.92 

 4877.70 

 4878.80 

 4879.90 

 4891.27 

 4894.90 

 4898.70 

 4906.77 

 4907.67 

 4913.69 

 4915.12 

 4916.86 

 4936.86 

 4940.85 

 4945.01 

 4945.81 

 4950.21 

 4951.41 

 4953.85 

 4955.16 

 4960.15 

 4969.85 

 4972.85 

 4979.90 



Faint but sharp. 



it u 



Faint. 

 Very faint. 



Sharp. 



Sharp, but faint. 



Sharp. 



Band. 



Sharp. 



Nebulous band. 

 Sharp, agrees. 



4983.06 \ Shar P' m *y 



\ 



4993.95 

 4997.60 

 4999.31 

 5001.55 

 5011.06 

 5012.50 

 5018.55 



5022.95 • 



5033.85 



agree. 



Faint. 

 a 



Agrees. 

 Faint. 



Sharp, agrees. 

 Faint. 

 May agree. 

 Faint, may 



agree. 

 Very faint. 



In regard to the accuracy that may be expected of the above posi- 

 tions, we feel sure that few of them are wrong by more than a tenth 

 of a wave-length, and those are of the class "Very faint," or " Broad 

 and nebulous." The better denned lines we believe to be correct to 

 within less than the above amount. The method of comparison we 

 have used admits of much greater accuracy than this, but the ill- 

 defined character of the air lines puts a limit to their accurate placing. 

 Compared with Thalen's positions, they should be credited with ten 

 times the accuracy at least. Some of Thalen's bands are resolved into 

 two or more in our instrument. 



Prof. John C. Draper projected his spectra upon a scale of wave- 

 lengths by means of a stereopticon, — a method which does not inspire 

 confidence in his results, when we consider the distortion produced by 

 projecting lenses. 



