What does the grapheme 'm̃' (m with a diacritical tilde) mean in English? Was it in use?

In a historical English book published in 1875, the grapheme 'm̃' (m with a diacritical tilde) is used in the title.

Ye parish of Cam̃erwell : a brief account of the parish of Camberwell : its history and antiquities / by William Harnett Blanch.
Language(s): English
Published: London : E.W. Allan, 1875.

Cover of the book:

Sources:
https://catalog.hathitrust.org/Record/100327885
Google Books

Cam̃erwell appears to be same as Camberwell in the book. Did the grapheme m̃ replace the consonant digraph mb here? Was this grapheme/character used in English? (Early Modern English or even before?)

Solution 1:

The answer lies in the link to "sigla" in tchrist's link and in Killing Time's comment about reading the relevant chapter.

The "tilda" is a siglum - a mark of some sort that the scribe uses as a form of shorthand. In essence it is no different from the common use of local intitialisms in an article or report, e.g.

The County Committee for Agricultural Development (CCAD) announced that there would be no action on the wheat crop. The CCAD also added that the rye crop is doing well.

As far as I am aware, in a given language there would be some standardised sigla to indicate a missing letter, e.g. in French "bête", the circumflex above the 'e' represented the omitted letter 's' - "beste", and in German the umlaut was an "e" - können" = koennen; über = ueber, but there was no general standardised version of sigla which, by and large, would informed you that a letter had been omitted, but not which one.