The excessive heat of the weather now proved a great hindrance to the expedition. They had already lost so many horses that a large part of their provisions, etc. had to be abandoned on various occasions.
On February 23rd, Mr. Stuart writes:
"Before reaching this place (the Hugh) five other horses gave in, and were unable to proceed further. I cannot understand the cause of the horses knocking up so much; every one of them has fallen off the last week. Whether it is the excessive heat or the brackish water of the Finke, I am unable to say.
Last night I tried some citric acid in the water of the Finke, and it caused it to effervesce, showing that the water contained soda."
It was afterwards ascertained that the horses were suffering from worms, which may partially account for their failing strength.