NEXT day I went to hear Professor Playfair's lecture. I found him already engaged in addressing his class when I entered, but took my seat close by the door, so quietly as not to attract any notice from him. It was a very pleasing thing to see this fine old Archimedes with his reposed demeanour—(such as I have already described it to you)—standing beside his table covered with models, which he was making use of in some demonstrations relative to mechanical forces. There is something in the certainty and precision of the exact sciences, which communicates a stillness to the mind, and which, by calling in our thoughts from their own giddy and often harassing rounds, harmonizes our nature with the serenity of intellectual pleasure. The influence of such studies is very well exemplified in the deportment of this professor. In lecturing, he expresses himself in an easy and leisurely manner, highly agreeable to the listener, although he does not seem to study continuity or flow of diction, and although his delivery is sometimes a good deal impeded by hesitation with regard to the words he is to employ. I have already described his features to you; but perhaps their effect was finer while he was engaged in this way, than I had before been prepared to find. I think one may trace in his physiognomy a great deal of that fine intellectual taste, which dictated the illustrations of the Huttonian Theory.

I waited to pay my respects to the professor, after the dismission of his class, and he invited me to walk with him to the New Observatory upon the Calton Hill. This building, which is not yet completed, owes its existence entirely to the liberality of a few private lovers of astronomy, and promises to form a beautiful and lasting monument of their taste. Mr Playfair himself laid the foundation-stone of it last year, and already it presents to the eye, what is, in my humble judgment, the finest architectural outline in the whole of this city. The building is not a large one; but its situation is such, as to render that a matter of comparatively trivial moment.