Company Names, addresses, dates:
  H.R. Clark, Keysville VA
  Keysville Pharmacy, H.R. Clark proprietor, Keysville VA (c.1901) ¹
  Keysville Drug Co, H.R. Clark Manager, Keysville VA (c.1904) ²

Notes:
Harry Robertson Clark (1860-1934)³ was a druggist in Keysville VA.
The 1880 US Census listed him as a "Clerk in Store". He would have been 20 years old at that time.

In 1901, a newspaper mention said that he was travelling for the Arthur J. Connor drug company of Boston, and that he formerly occupied the "Keysville Pharmacy".^Y

In 1904, a newspaper mention said that J.H. Hawkins sold his drug store and stock to H.D. Peters, and that Clark would be the active manager. It went on to say that the new store would be the Keysville Drug Company.

The 1910 US Census listed Clark's occupation as a Mail Carrier for the Rail Road, and the 1920 US Census also listed him as a mail carrier. But on the other hand, the Virginia Pharmacist lists H.R.Clark as a Pharmacist in Keysville in the years 1920 through 1935, so it's not clear if he was running the pharmacy during those years or not.⁴
His death certificate does say that he did indeed have 2 jobs, one as a druggist and one as a mail carrier, but it didn't indicate if he was doing them both at the same time.

Bottles:

This is a clear 5.1" bottle mouth-blown bottle embossed: H.R. CLARK / (mortar and pestle) / DRUGGIST / KEYSVILLE / VA