It is likely that Vida was a seond wife as it is unlikely that Mary Powys was a sister of 27 years younger than the (presumably) first born Mary Ann Charlotte.

Vida and then Captn Mars also had a daughter Mary Jane born 20 Sept 1840.

And Vida and then Lieut Mars had a daughter Eliza on 7 Sep 1823.

And Vida and then Brevet capt had a daughter Caroline on 19 Apr 1829.

And Vida and then Brevet Captain Mars had a daughter Isabella on 3 May 1835.

And Vida and then Lieut Mars had a son James born 8th June 1822.

And Vida and then Lieut Mars had a son Richard Henry Pohle born on 11 April 1819.
  (a slight conflict with Mary Ann Charlotte’s birth???)

____________________

Her burial record:

First name(s) Vider  [Original recolrd is more likely ‘Vida’]
Last name Morphett
Birth year 1801
Death date 01 May 1880
Death year 1880
Age 79Y 7M
Burial date 02 May 1880
Place St Thomas Mount,St Mary
Presidency Madras
Archive Reference N-2-61
Page 115
Catalogue Description Parish register transcripts from the Presidency of Madras, : 1698-1948
Record set British India Office deaths & burials

Additionally the original record states:

“Widow of the late Mars Morphett”

Cause of death: “Rupture of the heart”.

_______________

On 25 March 1876 she wrote a will in which she provided for her three unmarried daughters:

Caroline Morphett,
Mary Jane Morphett,
Mary Powys Morphett

She stated that they would have to live together as there was not much money left for them.

The will is written in strong legal language by someone who did their best to provide for most eventualities.