it was useless for Tartarin-Quixote to swear that he would be careful, that he would dress warmly, that he would take with him everything that might be needed, Tartarin-Sancho refused to listen.

The poor fellow saw himself already torn to pieces by lions or swallowed up in the sands of the desert, and the other Tartarin could pacify him only a little by pointing out that these were plans for the future, that there was no hurry, that they had not yet actually started.
Obviously one cannot embark on such an expedition without some preparation.

One cannot take off like a bird.

As a first measure Tartarin set about reading the reports of the great African explorers, the journals of Livingstone, Burton, Caille, and the like, there he saw that those intrepid travellers, before they put their boots on for these distant excursions, prepared themselves in advance to undergo hunger, thirst, long treks and privations of all sorts.
Tartarin decided to follow their example and took to a diet of "Eau bouillie".

What is called eau bouillie in Tarascon consists of several slices of bread soaked in warm water, with a clove of garlic, a little thyme and a bay leaf.