--- ../../derivations-0.55.20170612/tex/vcalc.tex       2017-06-02 22:55:37.000000000 +0000
+++ ../../derivations-0.55.20170613/tex/vcalc.tex       2017-06-19 01:24:42.857784778 +0000
@@ -251,9 +251,9 @@
 makes the~$\nabla$ operator useful.

 If~$\nabla$ takes the place of the ambiguous $d/d\ve r$, then what takes
-the place of the ambiguous $d/d\ve r'$, $d/d\ve r_o$, $d/d\tilde{\ve
-r}$, $d/d\ve r^\dagger$ and so on?  Answer:~$\nabla'$, $\nabla_{\!o}$,
-$\tilde{\nabla}$, $\nabla^\dagger$ and so on.  Whatever mark
+the place of the ambiguous $d/d\ve r_o$, $d/d\tilde{\ve
+r}$, $d/d\ve r^\dagger$, $d/d\ve r'$ and so on?  Answer:~$\nabla_{\!o}$,
+$\tilde{\nabla}$, $\nabla^\dagger$, $\nabla'$ and so on.  Whatever mark
 distinguishes the special~$\ve r$, the same mark distinguishes the
 corresponding special~$\nabla$.  For example, where $\ve r_o = \vui
 i_o$, there $\nabla_{\!o} = \vui\,\partial/\partial i_o$.  That is the
@@ -271,9 +271,11 @@
   written.  Refer to \S~\ref{vector:240}.
 }

+\index{Hamilton, William Rowan (1805--1865)}
 \index{Heaviside, Oliver (1850--1925)}
-Introduced by Oliver Heaviside, informally pronounced ``del'' (in the
-author's country at least), the vector differential operator~$\nabla$
+Introduced by William Rowan Hamilton and Oliver Heaviside, informally
+pronounced ``del'' (in the author's country at least), the vector
+differential operator~$\nabla$
 finds extensive use in the modeling of physical phenomena.  After a
 brief digression to discuss operator notation, the subsections that
 follow will use the operator to develop and present the four basic kinds
@@ -496,7 +498,7 @@
 }%
 ---what matters is not the surface's area as such but rather the area
 the surface presents to the flow.  The surface presents its full area to
-a perpendicular flow, but otherwise the flow sees a foreshortened
+a perpendicular flow but otherwise the flow sees a foreshortened
 surface, \emph{as though the surface were projected onto a plane
 perpendicular to the flow.}  Refer to Fig.~\ref{vector:220:fig-dot}.
 Now realize that eqn.~\ref{vcalc:flux} actually describes flux not
@@ -962,7 +964,7 @@
   If~(\ref{vcalc:divthm}) is ``the divergence theorem,'' then
   should~(\ref{vcalc:stokesthm}) not be ``the curl theorem''?
   Answer: maybe it should be, but no one calls it that.  Sir George
-  Gabriel Stokes evidently is not to be denied his fame!
+  Gabriel Stokes is evidently not to be denied his fame!
 }
 neatly relating the directional curl over a (possibly nonplanar) surface
 to the circulation about it.  Like the divergence
@@ -1157,7 +1159,7 @@
 themselves invariant.  That the definitions and identities at the top of
 the table are invariant, we have already seen; and \S~\ref{vcalc:350},
 next, will give invariance to the definitions and identities at the
-bottom.  The whole table therefore is invariant under rotation of axes.
+bottom.  The whole table is therefore invariant under rotation of axes.

 % ----------------------------------------------------------------------

@@ -1177,9 +1179,13 @@
 Like vector products and first-order vector derivatives, second-order
 vector derivatives too come in several kinds, the simplest of which is
 the \emph{Laplacian}%
-\footnote{
+\footnote{%
+  % diagn: new footnote; review
   Though seldom seen in applied usage in the author's country, the
-  alternate symbol~$\Delta$ replaces~$\nabla^2$ in some books.
+  alternate symbol~$\Delta$ replaces~$\nabla^2$ in some books,
+  especially some British books.  The author prefers the~$\nabla^2$,
+  which better captures the sense of the thing and which leaves~$\Delta$
+  free for other uses.%
 }
 \bq{vcalc:laplacian}
   \begin{split}
