all the oscillating magnetic pendulums (like this) were sold out but the shop promises that more have already been ordered, so i left my name and phone number and got them to save me one. then i went to porter books looking for other birthday presents for sarah and bought her a book about the history of libraries. this, i feel (somewhat uneasy), may be a present more for myself than for her. yet i feel sure that anyone who has ever had to move their books into a new home or agonised over what books to bring on a flight will excuse me for this. i am sure they too can't but help liking the tenth century persian vizier, abdul kasem ismail, who insisted on travelling with his personal library of over ten thousand books. his collection was transported by a caravan of more than five hundred camels walking in alphabetical order to facilitate acess to his books while on the go.