Letter from Lewis Carroll to Gertrude Chataway, Dec. 9, 1875:

This really will not do, you know, sending one more kiss every time by post: the parcel gets so heavy it is quite expensive. When the postman brought in the last letter, he looked quite grave. ‘Two pounds to pay, sir!’ he said. ‘Extra weight, sir!’ (I think he cheats a little, by the way. He often makes me pay two pounds, when I think it should be pence). ‘Oh, if you please, Mr. Postman!’ I said, going down gracefully on one knee (I wish you could see me go down on one knee to a postman — it’s a very pretty sight), ‘do excuse me just this once! It’s only from a little girl!’

‘Only from a little girl!’ he growled. ‘What are little girls made of?’ ‘Sugar and spice,’ I began to say, ‘and all that’s ni–‘ but he interrupted me. ‘No! I don’t mean that. I mean, what’s the good of little girls, when they send such heavy letters?’ ‘Well, they’re not much good, certainly,’ I said, rather sadly.

‘Mind you don’t get any more such letters,’ he said, ‘at least, not from that particular little girl. I know her well, and she’s a regular bad one!’ That’s not true, is it? I don’t believe he ever saw you, and you’re not a bad one, are you? However, I promised him we would send each other very few more letters — ‘Only two thousand four hundred and seventy, or so,’ I said. ‘Oh!’ he said, ‘a little number like that doesn’t signify. What I meant is, you mustn’t send many.’

So you see we must keep count now, and when we get to two thousand four hundred and seventy, we mustn’t write any more, unless the postman gives us leave.