drive for the telescope which should be independent of the power system's line-voltage fluctuation and frequency variations. On December 1, 1933, the final drive was installed at Lake Angelus. Its fundamental element was a synchronous motor the speed of which could be varied by means of frequency variations in the current, effected with a thermionic tube control. Worm gearing only connected the motor to the telescope. This drive proved itself to be everything that could be desired and has been adopted for other telescopes at other observatories.
Between 1930 and 1934 Director Curtis had shown the pictures taken at the McMath-Hulbert Observatory before many audiences, both scientific and popular, and through the University of Chicago Press the pictures secured a wide distribution all over the earth. The work was closely watched by the scientific world, and professional astronomers were generous in their praise.* 1.1 This early success was recognized by the Franklin Institute of Pennsylvania, which awarded the three founders the John Price Wetherill medal in May, 1933, "for their design and construction of novel apparatus for the making of motion pictures of astronomical subjects."
The reception of the solar motion pictures led R. R. McMath to suggest a solar tower telescope. With the help of President Ruthven, $20,000 was secured from the Rackham Fund as an initial grant. R. R. McMath and his brother, Neil Cook McMath (C.E. Cornell '14), then made an extended tour of inspection to other observatories, and in particular to Mount Wilson Observatory. All possible aid was given by the scientists at these observatories. It developed, however, that it would be most desirable to build an instrument which would take world rank as to size and light grasp. Soon after the McMaths' return from their trip, the founders of the McMath-Hulbert Observatory and H. D. Curtis held a conference and decided to proceed with plans for such an instrument. It soon became obvious that the cost of the instrument would greatly overrun the initial grant. A very substantial grant was then obtained from the McGregor Fund of Detroit, and in addition a number of individuals made generous contributions.
The resources available for design and construction proved to be particularly fortunate. R. R. McMath was president of the company in whose shops the 10 ½-inch instrument, with its complicated accessories and other equipment, had been built. Neil C. McMath was vice-president of the Whitehead and Kales Company of Detroit, one of the larger steel fabricators of this section of the country. Edison Pettit, of the Mount Wilson Observatory, put his accumulated experience in solar physics and solar observation unreservedly at the disposal of the McMath-Hulbert Observatory. Every effort was made to avoid mistakes which had been made in the past.
Ground for the new tower telescope was broken on July 16, 1935, and the instrument was completed, except for temporary optical parts, on June 30, 1936. A description was published in the University of Michigan Observatory Publications (Vol. 7, No. 1, 1937). Fortunately, the founders had purchased enough optical pyrex from the Corning Glass Company late in 1934. This alone permitted the work to be undertaken as soon as it was. Nevertheless, certain parts of the optical equipment were not
