The Editor,

Journal of Glaciology

Sir,

A technique for producing strain-free flat surfaces on single crystals of ice: comments on Dr H. Bader’s letter and Dr K. Itagaki’s letter

A recent attempt has been made to compare the surfaces of single crystals of ice prepared by the freeze-tap method (Reference Tobin and ItagakiTobin and Itagaki, 1970) with those prepared by Bader’s method (Reference BaderBader, 1972) using the interference microscope.

Figure 1 and Figure 2 show typical interference photomicrographs of the two methods approximately five minutes after their preparation at −10°C. Remembering that even, straight, and parallel interference bands indicate a flat, smooth surface, it can be seen that Figure 1 represents a surface which appears to be flatter and smoother than that of the surface in Figure 2. As previously observed (Reference ItagakiItagaki, 1972), Bader’s surfaces were always slightly curved, which can be readily seen from the slight curvature of the interference fringes in Figure 2.

Fig. 1.Interferogram of ice surface (freeze-tap method).

Fig. 2.Interferogram of ice surface (Bader’s method).

T. M. Tobin^*

U.S. Army Cold Regions Research and Engineering Laboratory,

Hanover, New Hampshire 03755, U.S.A.

5 December 1972