CHAP. IX. MEDITATION. 227 with, some savages., as by Mr. Dyson Lacy with the Aus- tralians of Queensland, and several times by Mr. Geach with the Malays of the interior of Malacca. What the meaning or cause of this action may be, cannot at pres- ent be explained; but here we have another instance of movement round the eyes in relation to the state of the mind. The vacant expression of the eyes is very peculiar, and at once shows when a man is completely lost in thought. Professor Bonders has, with his usual kindness, investi- gated this subject for me. He has observed others in this condition, and has been himself observed by Pro- fessor Engelmann. The eyes are not then fixed on any object, and therefore not, as I had imagined, on some distant object. The lines of vision of the two eyes even often become slightly divergent; the divergence, if the head be held vertically, with the plane of vision hori- zontal, amounting to .an angle of 2° as a maximum. This was ascertained by observing the crossed double image of a distant object. "When the head droops for- ward, as often occurs with a man absorbed in thought, owing to the general relaxation of his muscles, if the plane of vision be still horizontal, the eyes are necessarily a little turned upwards, and then the divergence is as much as 3°, or 3° 5': if the eyes are turned still more upwards, it amounts to between 6° and 7°. Professor Bonders attributes this divergence to the almost com- plete relaxation of certain muscles of the eyes, which would be apt to follow from the mind being wholly ab- sorbed.6 The active condition of the muscles of the eyes 0 Gratiolet remarks (De la Phys. p. 35), " Quancl 1'atten- tion est fixee stir qxielqtie image ititerieure, Pceil regarde. clans le vide et s'assoc.ie axitomatiqxiement a, la contem- plation cle 1'esprit." But this view'hardly deserves to be called an explanation.