Sentence:  A set of tables containing spectral intensities for 39000 lines of 70 <WSD>elements</WSD> , as observed in a copper matrix in a d-c arc , was completed and published . 
Meaning of the word marked with <WSD> tags:  any of the more than 100 known substances (of which 92 occur naturally) that cannot be separated into simpler substances and that singly or in combination constitute all matter