Calculating machines…

The first of Lemaître's calculating machines

La machine Mercedes au bureau de calcul

One of the Laboratory's Mercedes machines. Acquired at Lemaître's request, they were the first calculating machines at the Catholic University of Louvain.

His experience with the Differential Analyzer at M.I.T. in the early 1930s stimulated Georges Lemaître's interest in calculating machines. On returning to Belgium in February 1933, he went on using the machines in the context of his research work. Personally, he himself already owned some elementary adding machines, like the Addiator and the Curta. Those two “pocket” mechanical machines allowed adding, subtracting, multiplying and sometimes dividing.

His work becoming more and more complex over the course of time and requiring the use of increasingly improved materials, Georges Lemaître had the University acquire five Mercedes electromechanical calculating machines. Those machines were placed at the disposal of the students and as of 1935 installed in the loft of the Institute of Physics, located in the former college of the Premonstratensians in Louvain, future site of the Digital Research Laboratory.

He was so passionate about these calculating machines that he moved them to his apartment in Louvain during the war - fearing the Germans might requisition them. That in no way prevented the students from working normally. Conscious of the difficulty of living conditions, Lemaître authorized them to use the Mercedes machines he had at home, even when he wasn't there.

In order to bring out the full potential of the machines, Lemaître studied their internal functioning and soon handled them with great skill. The use he made of the Moon-Hopkins is very illustrative. Early in the 1950s, the president of Kredietbank, Fernand Collin offered him an accounting, calculating machine as a sign of friendship. Georges Lemaître quickly learned the programming and used the machine, designed to calculate banking interests and unable to divide, for calculations as complex as the form of galaxy clusters and the orbits of charged particles in the magnetosphere.

"On returning to Belgium in February 1933, he went on using the machines in the context of his research work. Lemaître also studied their internal functioning and soon handled them with great skill"


Creating the Digital Research Laboratory

"Décimalisation sur E 101"

An example of an instructions sheet for programming the Burroughs E101 calculator: a needle connected to the machine is inserted at each orange point, corresponding to a specific mathematical instruction.


The electronic age

" Even if Georges Lemaître took pleasure in handling and programming calculating machines, it was above all for him a means of improving his calculations and progressing in his research work"

Georges Lemaître et ses collègues

Photograph taken on the top floor of the former college of the Premonstratensians, where the Catholic University of Louvain's calculating machines were installed. This photo shows Lemaître, accompanied by some of his colleagues.