text:  The ordinary reader who has been fascinated by his glowing description of tropical scenery or his graphic picture of savage manners is a few pages on chilled by disquisitions on the height of the barometer the disk of the sun or the electricity of the atmosphere; while the scientific student who turns to his works for information on his favourite objects of study deems them strangely interspersed with rhapsodies on glowing sunsets silent forests and sounding cataracts