Large enough to overflow the Union Common Room, the world's biggest calculating machine received final approval from College engineers last week and will soon be dismantled for delivery to the Navy.

The mammoth "Mark II" computator, which technicians have been testing for the past year, will be shipped to the Dahlgren Proving Ground in Virginia within a month. The machine has, resided in Gordon McKay engineering lab since construction began in 1945.

Multiplies in a Second

The calculator, which was specifically designed for the Navy, exceeds in size and speed the machine now functioning in the Computation Building. Within a second it can multiply 7,869,438,763 by 9,321,643,868. Addition takes one-fifth of a second on the machine, which can handle 3500 numbers a minute.

With all this power, the computator really deals with only two figures zero and one. All numbers fed into it are translated into this "binary" scale before operations begin. Calculation is simplified by changing 6 into 110, 7 into 111, and 13 into 1101.

How Much is 6 Plus 7?

To add 6 and 7, the machine instead adds 110 and 111, and comes up with the answer 1101. This, however, is really 13. It's as easy as all that.

Control center of the computator is a 60-foot plastic wall, overspread with instruments, dials, and bulbs. Behind the panel lies 3000 square feet of steel framework, housing the multi-colored units which store and operate on the numbers.

If any one of the units break down, a new one can be plugged in immediately. The machine thus stays in operation 24 hours a day.

A million feet of yellow, red, black, and green wires winds in and out of the framework in the rear.

Teletypes Print Solutions

Off to the side a set of teletypes records answers to the problems, which in Navy hands will consist mainly of ballistics questions. Numbers can be fed into the calculator either by the dials or by punched tape.

The machine, which is electro-magnetic, differs basically from the College's own electro-mechanical calculator and the contemplated Mark III, which would be operated by vacuum tubes.

Seventy-five veterans constructed the instrument under the direction of Frederic G. Miller, research associate in Engineering Sciences and Applied Physics. Miller will follow the machine to Virginia.

Howard H. Aiken professor of Applied Mathematics, supervised all the computation projects.