Daniel Rutter bought himself this handsome old flashlight which he guesstimates is probably about seventy years old. As per typical, Dan spends about as much time discussing the history of flashlights as he does his new acquisition, which he was able to restore to working order with surprisingly little trouble. That “bullseye” glass on the end takes the already weak light and diffuses it more, which Dan speculates may have been to more readily emulate the light beamed from gas lanterns.
My new favourite flashlight [Dan's Data]
The glass is very weird, it makes the flashlight very interesting.
Because of the age, my guess is the glass is the appropriate shape technologically. A thin, clear piece of glass would break if you dropped or bonked the flashlight. Modern times are accustomed to plastic, or different types hybridized (chemically hardened) glass. If you had to make a true “lens” of glass 70 years ago that was rugged, then this may have been the appropriate solution.