It should be readily seen that if the primary mass has one dominant proportion while the appendage has another, there will be a serious clash and the final result will be the neutralization of both motives, resulting in either an insipid and characterless design or a downright lack of unity.
Appendages in Wood
The design of the small dressing table, [Figure 37], [Plate 16], with the mirror classing as an appendage, is an excellent illustration of Rule 4a. The main mass of the table is vertical in character and the mirror carries out or repeats the character of the primary mass by having a similar but subordinate vertical mass. In this instance it is so large that it has nearly the effect of a second primary mass.
As tangential junctions are difficult to arrange in wood construction and particularly in furniture, the break between the table top and the mirror has been softened by the introduction of a bracket or connecting link. The curves of the link cause the eye to move freely from the primary mass to the appendage and thus there is a sense of oneness or unity between the two masses.
The lantern in [Figure 38] becomes an appendage and is subordinated to the large pedestal or support. The tangential junction has in this case been fully possible and the eye moves freely from the vertical lines of the base to the similar vertical mass of the lantern without noticeable break.
Unifying Appendage and Primary Mass
The service of the dressing table, [Figure 39], with its three-division mirror makes the problem of adaptation of the appendage to the mass of the table, in accordance with the rules, much more difficult. Under the circumstances, about the best that can be done, at the same time keeping within the limitations of desired service, is to plan the mirrors in accordance with Rule 3b, with the dominant section in the center. To secure an approach to unity, each section of the mirror should echo the vertical proportion of the primary mass of the table.
Courtesy of Berkey and Gay