January 1939
James Bryce formalizes the project in a memo.

February 16, 1939
Bryce advises Lake that IBM President Thomas J. Watson has approved the project.

March 1939
IBM Board of Directors approves construction of an "Automated Computing Plant."

May 12, 1939
Bryce informs Lake that first appropriation of $15,000 is approved for the Harvard University machine. In addition, Bryce states that Lake will supervise the project at Endicott.

May 22, 1939
Bryce, Lake, Hamilton and Aiken meet in Bryce's office to further discuss the machine.

May 31, 1939
Hamilton informs Aiken that he has begun a tentative design of the value tape mechanism, a revised description of the essential operating points in computing sine "x," and a flow chart showing the sequence of events for that function. Hamilton also suggests that the program tape reading mechanism be 24 columns wide and subdivided into four sections of six columns each.

June 16, 1939
Hamilton outlines the shifting procedure required to determine the relationship of the decimal point in a quotient with variable dividend and divisor capacities.

June 20, 1939
Hamilton sketches the shift circuit required to obtain the decimal point location.

June 27 - Aug. 1939
Aiken works with Lake, Hamilton and Durfee at the Endicott Laboratory. They discuss relay contact points, top counter readouts and emitters, and Aiken sketches various circuits for the machine.

Lake and Hamilton decide to use Lake's ratchet type counter on the machine, enabling it to run at 200 cycles per minute.

August 31, 1939
Hamilton completes models of the tape feeding mechanism and tape rack, and tests begin on those two units.

September 15, 1939
Design of most of the special circuits is completed.

September 27, 1939
Hamilton and Lake estimate the machine's cost at $85,000.

October 2, 1939
Hamilton and Durfee outline tests to determine the resistance of the counter carry circuits. Their notes "indicate that no more than 15 counter positions could be used before the voltage drop would be sufficient to cause erroneous operation."*

October 3, 1939
Lake, Hamilton, Bryce and Aiken meet in Bryce's office to discuss the machine's cost. They agree that certain units may be eliminated from the original proposal but that provision be made in the machine's construction for their possible future restoration.

November 9, 1939
Hamilton informs Aiken that IBM has virtually completed the revised multiplying and dividing diagram and has completed and checked all functional diagrams.

* Extracts from an August 1944 internal IBM report.

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