What kind of tone does the author convey in the following passage:
After a short halt, under the blazing sun, the Sheikh again gave the order to advance. On, on! I struggled up, but my leaden feet almost refused to bear me. “Mohammed!” I called to my faithful Algerian, “I can do no more; I am done!”
In the excerpt you can see how the protagonist struggles to fulfill the orders of the Sheikh. He calls out to "Mohammed" and desperately yells, "I can do no more; I am done!"
From this we can conclude that during this moment he was very Desperate