While editing Hooke’s diary this week I came across the following nugget of information in an entry for 27 January 1673:

Dr Pell told me that somewhere in Porta was a way deliuered of stamping letters & figures in Sallow and afterwards plaining them almost out then steeping or boyling them in water wherby the letters would swell outwards and be fitt for printing or ye like or be embossed wth heads or the like.

Hooke and the other Royal Society Fellows were extremely interested in mechanical processes, and Hooke mentions new ways of printing or engraving quite a few times in the diary. Unfortunately Dr Pell’s rather vague reference ‘somewhere in Porta’ hasn’t yet helped me to track this particular suggestion down. Giambattista della Porta was a prolific Italian Renaissance author whose best-selling book ‘Natural Magick’ contains lots of interesting information about useful things you can do with science, including sections ‘on counterfeiting precious stones’ and ‘on beautifying women’. You can read the English translation online here  – but please don’t try the white lead cosmetic preparations at home.

What caught my attention was the fact that in the 1935 printed version of the Diary, the section quoted above had come out as ‘a way delivered of stamping letters and figures in tallow and afterwards plaining them almost out then steeping or boyling them in water’ . . .

Now, tallow, as we all know, is a kind of fat, and therefore probably not much use if you intend to boil your letters before printing with them. Whereas sallow is a willow plant – much more suitable for stamping, planing and boiling. Why did Hooke’s 1935 editors print ‘tallow’ for ‘sallow’? Probably because Hooke’s initial ‘s’ looks a bit like a ‘t’ in the manuscript, and tallow is a more commonly used word than sallow (or at least it was in the 20th century – I guess neither is particularly common now), and they weren’t thinking very hard about what they were writing. It’s easy, as an editor, to see the words that you expect to see, especially in Hooke’s rather cramped lines of text. I was pleased to find this, of course, because it reminds me that the mammoth job of re-editing the diary is actually worthwhile! But it also confirms with me again the importance of going back to the manuscript, even when there’s a printed text available. How many readers of Hooke’s diary over the years have scratched their heads over this section and wondered what on earth Hooke could have meant? (Well, okay, probably not that many since it’s never exactly been a best-seller.) As readers we’re used to assessing the quality of the text in front of us, whether Wikipedia entry, newspaper article, or scholarly tome, but it’s sometimes harder to decide whether an edition is a faithful representation of the original text or not, especially if you’re just dipping into it. Of course we can’t all go rushing off to the manuscript whenever we spot something unlikely in a printed text but if it’s the crux of your argument then it’s worth having a look.

While I’m on the subject I should add that going back to the original manuscript doesn’t just allow you to spot errors like this one, or omissions. A printed page, with its neat rows of type, each letter formed in exactly the same way, can never convey as much information as the manuscript. I always feel as though I know an author better when I’ve seen his work written in his own hand. Hooke’s meandering lines of tiny script with their many insertions of extra text squeezed in above a line tell, better than anything else, that he didn’t plan on other people reading his diary. All the more important to get the printed version right!