Early telephone. Historical artwork of three men gathered around an early telephone. The man at right is talking into the speaking tube. The first pra

---

Early telephone. Historical artwork of three men gathered around an early telephone. The man at right is talking into the speaking tube. The first practical telephone was developed by the Scottish-US inventor Alexander Graham Bell (1847-1922). In the 1870s, Bell performed experiments in converting sound waves into electrical impulses for transmission down wires (telephony). In 1876, he patented the telephone and co-founded a company to develop the technology.

---

Size: 4500px × 3900px
Photo credit: © MEHAU KULYK/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: abdomen, abdominal, abnormal, adenoma, alimentary, benign, body, bowel, canal, condition, digestion, digestive, disease, disorder, endoscope, endoscopic, endoscopy, gastroenterology, gastrointestinal, gastrology, growth, human, intestinal, intestine, intestines, medical, medicine, oncology, perianal, rectal, rectum, system, tract, tubular, tumour, unhealthy