I discovered My Viola and I, the autobiography of Lionel Tertis, in the library at Magic Mountain. It's a charming read with great anecdotes of musical life in the last century and including sections on the design of his own model and his physical problems that led him to stop playing. And there's a whole section at the end with playing advice:
'Long hair and locks over the right or left eyebrow are nauseating to look at and utterly useless in furthering musical capability.' On a more practical note: 'Portamento is not a discernible slide; it is an infinitesimal join. The art of its use is to avoid break, jerk or nauseous slide. It is a most necessary adjunct to legato playing and can either enhance or mar beauty of expression.' And he concludes: 'Do not forget that your playing will reflect your innermost self. Therefore, to make your power of expression worth listening to, it is necessary to mould your mind and action through life to all that is of the utmost sincerity.' Useful insight for budding soloists - there's more to life than a practice room.