Thanks, dje.
In the following Cartier history it is suggested that Jaeger gets credit for the original 1904 Santos.
Cartier Monde Company History:
www.fundinguniverse.com
l
I do not know how accurate that is. Can we trust a site that list the Cartier London office address as "Nightsbridge"?

On the other hand they do give a seemingly authoritative source: International Directory of Company Histories, Vol. 29. St. James Press, 1999.