The Band Spectra associated with Carbon

Abstract

IN an interesting letter to NATURE (August 8, p. 207), Prof. Birge has directed attention to a band system which I described as a “New Band System” in Proc. Roy. Soc., A, vol. 108, p. 349 (1925). More recently (NATURE, Sept. 5, p. 360) M. Baldet has written with reference to this system, pointing out that three of the six bands I recorded were measured and described by him in C.R., vol. 178, p. 1525 (1925). I should like to take the opportunity of saying that at the time of writing my paper I was not aware of this work of M. Baldet, and to him must be given the credit for the first recorded measurements of the system. At the same time, the discovery of this spectrum was first recorded by Prof. Merton and myself in Proc. Roy. Soc., A, vol. 103, p. 389 (1923), as follows: “It should be remarked that in addition, to the Comet-Tail bands which are degraded to the red, there are a number of very much fainter bands which are degraded to the violet, but are somewhat similar in appearance”. Under the conditions of production in helium mixtures, this spectrum is isolated along with the comet-tail bands and negative carbon bands from all other band spectra which might conceivably have rendered the identification from this brief description uncertain.