61-INCH MIRROR TO OPEN WORLD'S FAIR IN JUNE

Authorities of Harvard College Observatory are cooperating with certain observatories in the Middle West to receive a beam of light from the star Arcturus, which, having been turned into electrical energy and highly magnified, will turn on the thousands of lights at the Century of Progress Exposition in Chicago on the night of Thursday, June 1. If the night is clear, the telescope at the Yerkes Observatory of the University of Chicago will act as transmitter, but if it is cloudy through the Middle West, Harvard will have the honor.

The huge mirror, which Harvard will use if it is to open to Exposition, is to be one of the feature attractions of the "Astronomical Fair," to be held at the Harvard Observatory on Thursday, Friday, and Saturday evenings. The mirror is the third largest of its kind in the United States, and when finally mounted at the Oak Ridge station in Harvard, Massachusetts, will make up one of the largest telescopes in the eastern part of the country. It has been used in Cambridge for several years, but on account of the city lights and dusty atmosphere observation with it has been considerably limited.

To give the Observatory a genuine carnival atmosphere on the nights of its "Fair," there will be such attractions as booths for the sale of photographs of celestial bodies, a continuous motion picture of the recent total eclipse, and high powered telescopes with instructors close by to aid visitors in glimpses of the constellations. As the principal feature of the evening, however, there will be illustrated lectures at 7.30 o'clock and 9 o'clock by noted members of the staff.

The Cambridge Unemployment Relief Committee will receive the proceeds from the sale of tickets for the three evenings.