“Our previous series of Slides on Bright Line Spectra has been so well received that, by the request of some of our customers, we have gone to considerable trouble and expense to add the characteristic spectra of 33 more substances.

We are anxious to acknowledge the kindness of Prof. Sir William Ramsay, F.R.S., etc., who, in spite of the great demands on his most valuable time, has, with his usual courtesy, most kindly assisted us in the production of these Slides. These can only be shown in conjunction with No. 1 of this series, which is used with each of the others in turn.”