"In ultrasonic memories, it was customary to store up to 32 words end to end in the same delay line. The pulse rate was fairly high, but people were much worried about the time spent in waiting for the right word to come around. Most delay line computers were, therefore, designed so that, with the exercise of cunning, the programmer could place his instructions and numbers in the memory in such a way that
the waiting time was minimized. Turing himsdf was a pioneer in this type of logical design. Similar methods were later applied to computers which used a magnetic drum as their memory and, altogether, the subject of optimum coding, as it was called, was a flourishing one. I felt that this kind of human ingenuity was misplaced as a long-term investment, since sooner or later we would have truly random-access memories. We therefore did not have anything to do with optimum coding in Cambridge.
Although a mathematician, Turing took quite an interest in the engineering side, of computer design. There was some discussion in 1947 as to whether a cheaper substance than mercury could not be found for use as an ultrasonic delay medium. Turing's contribution to this discussion was to advocate the use of gin, which he said contained alcohol and water in just the right proportions to give a zero temperature coefficient of propagation velocity at room temperature"
This is debatable at the very least, since Manchester Baby was completed an year earlier and Manchester Mark 1 was operational before EDSAC ran its first program.