Appeal No. 97-2359
Application 07/894,260
distribution”. What is recited is “substantially mono-
dispersed particle size”. In view of appellants’
specification, it appears that “substantially mono-dispersed
particle size” has the same meaning as “substantially uniform
particle size distribution” and “substantially uniform size”
(page 1, line 19; page 7, lines 1, 19-20 and 24). Appellants,
however, do not state what is meant by “substantially” in any
of these terms.
Whitehead teaches that if the ratio of divalent to
trivalent iron salts used to form the oxide particles is too
low, the particle size becomes more heterogeneous, but the
particles nevertheless can be silanized (col. 11, lines 44-
51). This teaching indicates that uniformity of particle size
is a result-effective variable and that particles having a
uniform particle size are desirable. Thus, in view of this
teaching, it would have been prima facie obvious to one of
ordinary skill in the art to use conventional techniques to
obtain a substantially uniform particle size, with the optimum
particle size distribution being determined through no more
than routine experimentation. See In re Boesch, 617 F.2d 272,
-5-5
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