[436] Sitzungsber. kaiserl. Akad. Wiss. Wien, 1910, 119, IIa, 576.
The most intense lines of the arc spectrum are the following:
| 3353·90 | 3630·93 | 4314·31 |
| 3372·33 | 3642·99 | 4320·98 |
| 3558·69 | 3907·69 | 4325·22 |
| 3567·89 | 3912·03 | 4374·69 |
| 3572·73 | 4020·60 | 4400·63 |
| 3576·53 | 4023·88 | 4415·78 |
| 3614·00 | 4247·02 | 6305·94 |
Fowler (loc. cit.) examined the arc spectrum with reference to solar spectra. For detection of the element in minerals see Crookes (loc. cit.) and Eberhard (loc. cit.).
The purity of scandium preparations may be determined by the following tests:
(1) Precipitation with thiosulphate in boiling solution should remove all the rare earth content from solution.
(2) The iodate test for thorium should give no result.
(3) The oxide must be perfectly white, and salt solutions show no absorption.
(4) R. J. Meyer has found that whilst 0·5 per cent. of thoria cannot be detected spectroscopically in scandia, the magnetisation coefficient affords an exceedingly delicate test. The value for pure scandia is -0·12 × 10⁻⁶, the oxide being diamagnetic; for scandia with 0·5 per cent. thoria the coefficient was found to be +0·04 × 10⁻⁶, the mixture being paramagnetic.