Thanks Ron,

It must be LtCol. John Grant. The dates corresponde.

Now, Alferes and fellow observation officer José Clemente Pereira must have learnt a valuable lesson - never lend a horse (bought on credit) to another officer. I wonder if he ever got his reparation.
Interestingly enough, this José Clemente Pereira rose to be Minister on several occasions (including War and Finances) in D. Pedro II's Brazil. He had the nickname of José Pequeno (Little José).

Thanks again,

Jorge