There was an error in the original version of figure 6, the correct version is given below.

Figure 6. Temperature dependence of the exponents m and n in KH2PO4: (a) c axis, (b) a axis.
The following corrections should also be made:
(i) in the tenth line from the bottom of page 5495 `about 0.95' should read `about 0.05',
(ii) in the eighth line from the bottom of page 5495, `increase towards unity' should read `decrease towards zero',
(iii) in the seventh line from the bottom of page 5495 ` m, n = 1' should read ` m, n = 0'.