Robert Darwin autograph letter signed to the Darwin family attorney and financial advisor, Thomas Salt. Marked ''Wednesday 26'' by Darwin, docketing on verso by Salt's office reveals the date as 26 January 1842, which is shortly after Charles Darwin published ''The Voyage of the Beagle''. Robert Darwin's success as both a physician and investor allowed him to fund his son's research on the Beagle. Here he writes in part, ''...I have a cold or I would come at once to you - I can call tomorrow upon you I dare say, unless you can without trouble give me your instructions by a note. Dear Sir yours truly / RWDarwin''. Letter on card-style bifolium stationery measures 4.375'' x 7.125'' as folded. Small hole above fold, else near fine condition.