It can be surmised, therefore, that surveying instruments, as well as instruments for other purposes, were produced in both brass and wood simultaneously by many of the New England makers in order to provide suitable instruments in a flexible price range to meet the demands of the trade. Whereas today modern manufacturing methods make it possible to produce instruments in a wide variety, both in quality and price, to suit the needs and capabilities of every prospective purchaser, the production facilities of the 18th century were much more limited. The constant factor of skilled hand labor was costly. Metal was expensive. As evidenced in the records of Daniel Burnap, for instance, it was possible to produce surveying compasses in brass in two grades, presumably one more elaborate than the other. Yet Burnap's prices ranged between six pounds and four pounds for the metal instruments, making them still well out of reach of many of the would-be surveyors. Accordingly, Burnap--and presumably numerous other instrument makers of the period--produced from wood an economy model that sold for not more than two pounds, thus placing the item within the reach of the nonprofessional surveyor. This theory is supported amply by the discovery that several of the instrument makers who worked in brass also made instruments of wood during the same periods. In addition to the evidence in the records of Daniel Burnap, there are the surviving surveying instruments in brass and wood made by Samuel Thaxter, Thomas Greenough, and John Dupee, leaving little if any doubt that the reason for producing surveying compasses and similar items of wood during the 18th century was to satisfy the need for reasonably accurate yet inexpensive instruments. Surviving Instruments The fact that the surviving examples of the wooden instruments were produced only in New England seems to indicate merely that the New England instrument makers were more familiar with the use of wood as a material, and had greater facility in working with it. Undoubtedly other instruments produced by the 18th-century American makers have survived in addition to those already found. Quite likely examples of these wooden instruments still remain hidden in unexplored attics and other repositories. Yet, if the few thus far discovered is any criterion, the number ultimately recoverable will probably be but a fraction of the great number produced by the 18th-century makers during the half century or more in which they worked. Even allowing for those probably destroyed in the natural course of events, one cannot help but wonder what has happened to the remainder.