I often find chemical formulae in my documents that require the numbers to be made subscript. e.g. H2O should be H2O and H2SO4 should be H2SO4. I am trying to write a macro that will take numbers from a highlighted selection and subscript numerical values. I am not very good at programming. I have tried variations on the following:

```vb
Sub SubscriptNumbers()

    Dim Char As String

    For Each Char In Selection.Characters

            If Char >= "0" And Char <= "9" Then
                Char = Char.Font.Subscript
            End If

    Next Char

End Sub

```

But I get confusing errors (Compile Error: `For Each control variable must be Variant or Object`; but if I change Char to variant, it runs without error but doesn't appear to do anything). I know that there is an aversion from people in the know about using 'Select' but my doc will likely contain lots of other numbers that should not be made subscript.