D O C U M E N T 9 0 N O V E M B E R 1 9 2 7 9 3 Then that comes to an end, on to the experiment We figure out, just think! The secret of Nature.[5] — But meanwhile the little son Still dreams of dinner And patiently allows us The whole masquerade. — If then we get ready to leave You should see the little son! He screams like a madman And his Papa is delighted. — Today, I’m quite sure of this, No one’s scared of Bolshi The group of friends celebrates The familiar witching hour. — With the crack of the clock of life Every creature, with friends dear, Must enjoy himself splendidly In each year. 90. To Georg Count von Arco [Berlin,] 19 November 1927[1] Dear Count, I thank you heartily for your kind message.[2] I believe that it is not out of the question that a tuning fork in connection with the [ ][3] mechanism that you de- scribed could replace the pendulum as an instrument for measuring time. It is fur- thermore possible that the present apparatus could already be applied to a test of the uniformity of the Earth’s rotation. I would, however, consider it to be expedient to publish a sufficiently detailed article describing what you have thus far accom- plished in astronomical and physical journals—e.g., the Astronomische Zeitschrift, the Zeitschrift für Physik, and Naturwissenschaften—so that those who are dealing with the relevant scientific problems will be made aware of this new method of measurement. Kind regards, A. Einstein