268 M. KriePs Mean Results of Observations 



because, however much we press upon the former, such is the 

 power of its muscles, and such is the tendency of both eyes to 

 execute similar movements, that the pressed eye directs its op- 

 tic axis as near as possible to the point contemplated by the 

 right eye, or that which is free. The attempt, therefore, to 

 force the left eye into an angular position different from the 

 right eye, is immediately resisted ; and while one of the doub- 

 led images is descending, in consequence of the ascent of the 

 pressed eye, the pressed eye, so far from having changed its 

 angular position, will be actually contemplating the fixed im- 

 age, provided the other eye is contemplating that image, or it 

 will direct itself to any other part of space to which the right 

 eye may direct itself. 



3. It is a circumstance not a little remarkable, that it never oc- 

 curred to Dr Wells, nor, so far as we know, to any person else, 

 to press upwards the two eyes at the same time. When this is 

 done, the two spectral impressions will be seen to move, and to 

 rise through spaces so obvious to the dullest perceptions, as to 

 put an end for ever to the extraordinary dogma, that they are 

 capable of being put in motion only by the action of the vo- 

 luntary muscles. 



As Mr Charles Bell has not been sensible to the two first of 

 the preceding observations, we recommend to his notice this 

 last experiment ; and we trust that he will have the candour 

 to communicate the result of his observations to the Royal So- 

 cieties of London and Edinburgh, and to acknowledge that he 

 has discovered the true locality of that hallucination which he 

 dared to ascribe to the functions of a sound mind. 



Art. XIV. — Mean Results of Observations with the Thermo- 

 meter and Barometer at Batavia. By M. Khiel, M. D. 

 Communicated by Professor Moll of Utrecht. 



W\th the view of obtaining a measure of the mean tempera- 

 ture of the equator, we requested Professor Moll to obtain for 

 us observations on the mean temperature of Batavia, which is 

 situated within 6° of the equinoctial line ; and he was so kind 

 as to favour us with the following communication : 



"The following abstract ismade from the Transactions of the 



