The speed of the .177 is pretty impressive and I've always wanted to try out the whisper.

A more modern version of the one you remember:
http://www.amazon.com/Crosman-M4-177-Pne...
A more accurate single shot version:
http://www.amazon.com/Gamo-Whisper-Silen...
And more like the caliber Lewis and Clark used:
http://www.amazon.com/Benjamin-BPBD3S-Bu...

Still pretty amazing given the time period.

Reservoir charging may have been tedious but look at the advantages.

1 no powder to worry about keeping dry or running out of. Ditto flint.

2 no explosive flash in you face with its risk.

3 no smoke cloud to show your location

4 quicker cycle time between shots

5 quiet

I can see the advantages of this weapon for exploration and other uses. The long charging on the air chamber is a big negative for general military use. Likely expense as well at the time.

Yea for that Lewis and Clark air rifle. Not the BB gun I grew up with, for sure. But I understand that it took someone pumping all evening to have it ready to demonstrate to the tribes the next day.

That was very interesting. Thank you for posting it.