He had thus decided to travel through the desert to Tisheet in the north .
As the circumstances were pieced together , it appeared that Houghton had been discouraged from taking the direct route to Timbuktu .
Houghton had thus decided to travel through the desert to Tisheet in the north .
As the circumstances were pieced together , it appeared that Houghton had been discouraged from taking the direct route to Timbuktu .