Been around for a long time. Lewis and Clark had one on their expedition.
http://www.bing.com/search?q=lewis+and+clark+air+rifle&src=IE-SearchBox&FORM=IESR02
Another reason to appreciate FR - you learn the darnest things.
I had no idea gun manufacturing technology and capabilities were so sophisticated 220 years ago!
“With a full air reservoir, the Girardoni air rifle had the capacity to shoot 30 shots at useful pressure. These balls were effective to approximately 125 yd (114 m) on a full air reservoir. The power declined as the air reservoir was emptied.”