Lettre No 3337. Galileo to the States General of the Netherlands, August 15th 1636

“’I have such a time- measurer that if 4 or 6 examples of this instrument were constructed, and if they were allowed to operate at the same time, we would find that in confirmation of their accuracy, the times measured and indicated by these time-measurers would show differences of only one second, not only from hour to hour, but from day to day and from month to month, so uniform would be their operation; these clocks are really admirable for the observers of motion and celestial phenomenon, and in addition, their constructio