Abstract
The equivalence principle as well as the spin-two character of the weak gravitational field lead to difficulties in the measurability analysis of this field which are not encountered in Bohr and Rosenfeld's corresponding inquiry into the electromagnetic field. To meet these difficulties, atomic elastic structures are proposed as gravitational field detectors whose parameters (masses, total volumes, lattice and elastic constants) are adjustable. The limitations imposed by the uncertainty principle and by the radiation reaction of the detectors on the determination of the amplitude, frequency, and direction of the field are then exhibited. Finally, the relevance of the present work to the investigation of DeWitt and to Einstein's full theory of gravitation is briefly considered