Effect :
Borrowed pack laid on table and spectator cuts. He
chooses either heap, cuts this and looks at the bottom card of the
cut. The cut portion is replaced and the pack reassembled. The
card looked at is named and the magician spells it out, taking off a
card for each letter. and at the end of the spelling shows the card
selected.



HOW IT'S DONE.... 
When anyone cuts a pack it is usually divided near the
center. The pack having been cut and a pile chosen, invite the
spectator to cut that heap and illustrate by cutting the remaining
pile about the middle. When he does likewise, make an estimate of
the number he cuts off, usually from ten to fifteen. He then looks
at the bottom card of his cut and replaces the cards. Pick up this
pile and place it on top of the other portion, thus reassembling the
pack with the selected card at the number from the top as
estimated by you.
False shuffles and cuts may follow according to your ability. Have
the card named. Suppose the 4C is the card, and you estimate it is
about fourteen cards down. Spell out 'The Four of Clubs' and the
card shows up either on the B or the S. In either case act as if that
was what you intended. If it doesn't fall at S throw out another
card and say 'Four of', and if that is the card say 'Clubs'; but if
not, then throw still another card and with it say 'Clubs'. In other
words you fit the spelling to the number of cards you estimate the
spectator cut. By adding or omitting the 'of' and the final 's' of the
suit the spelling can be made flexible enough to fit all cases. With
but little practice the number of cards can be estimated to within
one or two.