What is "burthens"

Usage examples of "burthens".

This burthens us with an incurable effect of unreality, and I do not see how it is altogether to be escaped.

The burthens unstrapped from the pack-saddles very quickly furnished our den: a couple of quilts spread upon the floor, with a carpet-bag at the head of each, became capital sofas - portmanteaus, and hat-boxes, and writing-cases, and books, and maps, and gleaming arms soon lay strewed around us in pleasant confusion.

The ground floor is used for warehouses, the first floor for guests, and the open court for the temporary reception of the camels, as well as for the loading and unloading of their burthens, and the transaction of mercantile business generally.