Civilian Knapsacks.

Civilian knapsacks were of many different sizes, some were home made from a haversack. The flap on the knapsack was commonly secured by three buttons, but it was not unusual to see them with only two buttons. Chest straps were fitted to some to stop the pack from moving about. The chest strap was made in two parts each half was stitched to a shoulder strap and to secure it across the chest was a buckle.
Some were painted to make them water resistant, but the majority seem to have been plain linen or hemp.

This image shows the attachment of the chest strap on my own knapsack. This was made by converting a haversack.

Detail of the making of the eye on the flap on the inside.

Detail of the eye on the outside of the flap.

A green painted knapsack.

http://www.scribd.com/doc/230847766/Knapsacks;

1690.

18th century travel in Europe.

Ferdinand Kobell

German (Mannheim, Germany 1740 - 1799 Munich, Germany)

Traveller with a Knapsack.

"He was on horseback; I on foot bearing my knapsack".

"After breakfast, I bade my host farewell, buckled on my knapsack and left".

Daniel Boone. The Project Gutenberg EBook of Daniel Boone, by John S. C. Abbott.
My understanding of the above quote, is that Boone's knapsack was equipped with a chest strap.

A Knapsack with strap and buckle.
Lieutenant Archibald Bailey of the 60th
Regiment to Colonel Bouquet.

"we had Pitched our Tent and made a very Large Fire we pull’d out our Knapsack in order to Recruit ourselves every one was his own Cook our spits was Forked Sticks our Plates was a Large Chip as for Dishes we had none”
George Washington 1748 at 16 years of age.

"Militia minutemen hold themselves in readiness at a minutes warning, compleat in arms and ammunition; that is to say a good and sufficient firelock, bayonet, thirty rounds of powder and ball, pouch and knapsack." (Town of Roxbury Resolves, December 26, 1774.) 

“I gave orders to them to go home and fetch their arms whether guns, swords, pitchforks, axes or whatsoever might be of use against the enemy and for three days provision in their knapsacks”

Letter to Gov. Morris, from Conrad Weiser, Esq. 10/27/1755