Sentence:  Mademoiselle de Roissi's voice ... is quite free from that <WSD>throatiness</WSD> of sound, an invariable characteristic of French voices, which, had we no evidence to the contrary, would lead us to suppose, that Mdlle. de Roissi had studied vocalization in Italy ... 
Meaning of the word marked with <WSD> tags:  (with reference to a voice) The property of being throaty; roughness, coarseness.