TO REV. LEWIS CAMPBELL.

                                                                                 Marischal College,
                                                                         Aberdeen, 5th January 1860.

     . . . I have been publishing my views about Elastic Spheres in the Phil. Mag. for Jany., and am going to go on with    it as I get the propns. written out. I have also sent my experiments on Colours to the Royal Society of London, so   I have two sets of irons in the fire, besides class work. I hope you get on with Plato, and that your pupils are all  Theætetuses, and that wisdom soaks like oil into their inwards. There is a man here who is striving after a general  theory of things, but he has great difficulty in so churning his thoughts as to coagulate and solidify the vague and   nebulous notions which wander in his head. He has been applying to me very steadily whenever he can pounce on    me, and I have prescribed for him as I best could, and I hope his abstract of his general theory of things will be   palatable to the readers of the British Ass. Reports for 1859.