Writing instruments (19th century): Identify the person credited with inventing the first practical fountain pen with a reliable feed. Context: Consider the capillary feed innovation that enabled consistent ink flow and commercial success (1880s). Choose the correct inventor.

Given data

• Device: first practical fountain pen with dependable ink feed.
• Era: 1880s commercialization.

Concept / Approach
Distinguish earlier attempts from the design that solved flow reliability for everyday use.

Reasoning
Lewis E. Waterman patented an improved capillary feed (1884), creating the first broadly reliable fountain pen and founding the L. E. Waterman Company.

Notes on options
Poenaru patented an early reservoir pen (1827) but not the reliable modern feed; Purvis made improvements (1890) after Waterman; Bíró invented the ballpoint, not the fountain pen.

Final Answer
Lewis Edson Waterman.