An Investigation of the Spectra of Bessemer Flames. 



93 



oxygen gases between the pressures mentioned has been investigated. 

 The results confirm the applicability of Boyle's law. In the case of 

 oxygen nothing has been seen of the anomalies encountered by Bohr, 

 especially in the neighbourhood of a pressure of 0*7 mm. 



" An Investigation of the Spectra of Flames resulting from Opera- 

 tions in the Open-hearth and ' Basic ' Bessemer Processes." 

 By W. IS 1 . Hartley, F.K.S., Eoyal College of Science, Dublin, 

 and Hugh Eamage, A.B.C.Sc.L, St. John's College, Cam- 

 bridge. Beceived November 15, 1900, — Bead February 21, 

 1901. 



(Abstract.) 



Three papers on "Flame Spectra," by one of the authors, were 

 published in the 'Philosophical Transactions ' for 1894. Parts I and 

 II, "Flame Spectra at High Temperatures," and Part III, "The 

 Spectroscopic Phenomena and Thermochemistry of the Bessemer 

 Process." The results in the last of these papers had reference to 

 the phenomena observed in the flames of the " acid " Bessemer 

 process ; the present paper deals mainly with an investigation of 

 the Thomas-Gilchrist or " basic " process. 



The Cleveland district of Yorkshire was chosen as the principal 

 centre ; owing to the interest taken in the work by Mr. Arthur 

 Cooper, Past President of the Iron and Steel Institute, and in con- 

 sequence of the courtesy and attention shown us, the North Eastern 

 Steel Company's works at Middlesbrough were selected. 



It was found necessary at the outset to have three observers at work 

 simultaneously, and the authors were voluntarily and ably assisted by 

 Mr. E. V. Clark, A.B.S.M. Photographs of the plant and the flames, 

 at different periods of the blow, were secured by means of a small 

 Anschiitz camera and Goertz lens ; eye observations were made with 

 a small direct-vision spectroscope ; photographs of spectra were taken 

 with the spectrograph described in ' Philosophical Transactions,' A, 

 vol. 185, p. 1047, and the times of the exposures, &c, were observed 

 and recorded in a note-book. This work was not accomplished with- 

 out some difficulty, which was occasioned by the large quantity of lime 

 dust blown into the air. 



The spectroscopic results were quite different from those previously 

 obtained, as the continuous spectrum was much stronger. Many 

 lines and bands new to the Bessemer flame spectra have been observed 

 in addition to the spectra of the common alkali metals, iron, and 

 manganese. Thus rubidium, caesium, calcium, copper, silver, and 

 gallium have been identified. The crude iron, the ores, limestone, 



