London — Two collections that were sold during the same week earlier this year here at Sotheby's were reminiscent of the ''compare and contrast'' examination questions one used to struggle with at school.
At first there appeared very little in common between the Thomas F. Flannery Jr. collection of medieval and renaissance European works of art and the W. J. Shepherd collection of ''treen'' (an old English word for small domestic items made of wood). There were great disparities in social background, age, and monetary value between the collections. Yet they were both small and portable, and they showed an equal weight of scholarship, scope, and sheer visual pleasure.
Both collections were works of art in their own right. They had stature solidly based on years of study, search, and research. They presented to the modern viewer an immensely valuable insight into the tastes and customs of the past, as well as the values lost or inappropriate to our age.
First came the Flannery collection, which winged its way to London at the express wish of the late Chicago collector. It was in every sense a ''private'' collection, previously known chiefly eamong scholars of the renaissance and medieval periods, to whom Mr. Flannery had always given generous access.
Mr. Flannery spent over 30 years patiently assembling the collection; indeed, many of the footnotes in the catalog compared items with those in great public collections in both Europe and America. Most of the early works - ecclesiastical figures and vessels - probably indicate the power of the church at this period to command the finest of the available craftsmanship. There were madonnas, saints, angels, and monks which, fashioned in ivory, gilt bronze, wood, and stone, express that quiet and refined piety so evident in the iconography of medieval Christianity. At the same time, the chalices, caskets, reliquaries, and monstrances displayed a profusion of jeweled and enameled decoration somewhat at odds with the solemnity of the figures.
On the auction floor, many of the objects sold at astonishingly high prices - which paid tribute to the consummate skills of craftsmen working in techniques we can no longer emulate or afford. Apart from the carved and cast figures, there were fine examples of the medieval champleve enamels and the later painted enamels from Limoges, France; early stained glass; and the work of the silversmith and goldsmith. Perhaps the most spectacular item in the collection was a small group of renaissance jewels, two of which had originated in the Portuguese crown jewels.
One could scarcely imagine a greater contrast to this dazzling array of the accouterments of lords spiritual and temporal than Mr. Shepherd's collection of treen. This collection, described as ''the most comprehensive of its kind ever formed,'' demonstrated just how wide the range of treen can be.
The collection began in the 17th century, where the Flannery collection left off, and covered most of the next two centuries; almost all the items were British, with a few Scandinavian exceptions. While the works of art were definitely intended to display wealth and rank, the treen objects represented the unselfconscious daily activities of home, both from above and below stairs.
The household items included materials for lighting and heating, knitting, spinning, and playing games - as well as hosts of utensils from kitchen, dairy, and laundry. Included, too, were the tools of many trades, as well as medical items, agricultural implements, and reminders of coaching days.
These objects were clearly not intended to be taken for granted as merely functional. Decoration broke out in all directions: Turned, carved, painted, gilded, and inlaid objects took their place with plain ones, in which the natural beauty of the wood was ornament enough. No piece was too humble to be made beautiful: One received the distinct impression that our forbears relished a ceaseless activity. Originally made in large quantities, these charming bygones are still in reasonably plentiful supply and well within the means of the ''modest'' collector.
It will not, however, be a modest collector who assembles a collection to rival Mr. Shepherd's. As with the Flannery collection, it was the work of a lifetime. Even though the fruits of those years of patient labor are now deliberately scattered to the ends of the earth, both collectors hoped their efforts would serve to inspire a new generation of scholar-collectors.