6 PREFATORY NOTE. 



Publication No. 65, p. 70), where the probability of a band at 14 (i is 

 based upon two spectrometer settings and only three observations. 



In Carnegie Publication No. 65, Appendix V, "Note on Blowing 

 Quartz Fibers," the originator of the method was then unknown to the 

 writer. Since then it has been found that in addition to shooting quartz 

 fibers the method of blowing them is fully described by Boys in the London 

 Electrician, p. 220, Dec. 11, 1896, "Blowing and Shooting Quartz Fibers." 



Prof. E. F. Nichols has written me that he found the method in 1891, 

 and exhibited it at the jubilee celebration of the Physikalische Gesellschaft 

 in Berlin in 1896. 



In Carnegie Publication No. 35, p. 51, line 10 from the bottom should 

 read: "Carbon dioxide is the only gas studied which has no strong absorp- 

 tion bands except at 4.5 \i and 14 /*." 



W. W. COBLENTZ. 

 Washington, D. C, May, 1908. 



