SOUTH HADLEY, Mass, ip)— Copies of old and rare books soon will be available to Mt. Holyoke college students through acquisi tion of a series of microfilms by Williston Memorial library, in co operation with Smith and Amherst colleges. These miniature films, which can be run off the reading machine much like a motion picture pro jector, will allow students to read rare editions of Chaucer, Bacon, Caxton and historical records here tofore inaccessible. At the end of the first year of the joint subscription, Mr. Holy oke will have 100,000 filmed pages that can be filed compactly in cases of 18,000 pages each.