Check, re-check and then check again
I have read many Tauchnitz books and browsed many others and I don’t think I have ever come across a spelling mistake. There are one or two small printing errors – the first printing of volume 35 managed to spell Tauchnitz’s own name wrongly on the title page- but these are very few and far between. Remember these are books typeset and printed in Germany but in the English language. For the people who set them up they were effectively foreign language books. There were no automatic spellcheckers when they were produced. The firm had no London office where it employed English language editors, and I have no knowledge of it employing British staff in its Leipzig office, although it seems possible that it may have done so. The early volumes though carried a note on the front cover saying ‘The corrections of the press by Dr. Fluegel’, who doesn’t sound very British.
How on earth did they do it? It’s clear from his correspondence that Bernhard Tauchnitz himself was, or became, a fluent English speaker. But there must have been some limitations to his command of English at least in his younger days, and in any case he would hardly be reviewing every text himself in detail. Most of the books the firm published had already been published in Britain, so there would have been a printed text to work from rather than the author’s manuscript. However in many cases the Tauchnitz Edition came out within a few days of the UK edition, or even in some cases earlier, so they must sometimes have been working from early proofs, rather than a final text. And I assume that the people actually setting the type to create the stereotype plates were not native English speakers. A few spelling or printing mistakes would certainly have been excusable.
The firm didn’t just publish in English. They also published in German and in French as well as a large number of Latin books. I can’t vouch for the level of accuracy in these, but it seems fair to assume that attention to detail was one of the firm’s strengths. And they applied the same attention to numbers as well as words. When they published Dr. Bruhn’s ‘New manual of logarithms to seven places of decimals’ in 1970, it gave details of five separate examinations of the logarithms for accuracy, the last two of them read from the stereotype plates. As the book contains over 600 large pages of closely packed figures, this was no mean feat. It was accompanied by an offer from the publisher to pay one Friedrichsd’or (a Prussian gold coin named after Frederick the Great) as a prize for finding a typographical error. However the proof reading wasn’t perfect. By the time the book was reprinted in 1903, six errors had been found and corrected.