1869.] Oleography. 709 Rome was overrun by the barbarians ; but the tide of Empire had onby surged Westward, and Western Europe, pass- ing through the same architectural and governmental stages, as had Greece and Rome, produced anon the same results. At this point, Architecture, while re- taining all the utilitarian, and perfecting its artistic qualities, had begun to ex- hibit itself from a Scientific point of view. Its constructions were based upon the theoretical knowledge of certain physical laws, and the ability of ren- dering those theories practical, and were therefore a branch of Mechanics. Architecture as a fine art occupies to- day no higher place than it did during the times of Michael Angelo, j-et it has advanced greatly as one of the useful Sciences, and in its adaptation to the needs and comforts of mankind has kept pace with most, and outstripped many contemporary Sciences. Here, again, its analog}' with the art of Government is visible, for while the aim of the architect of to-day seems to be the preservation of the artistic ele- ments in subservience to the require- ments of utility, that of the political economist is evidently towards a Gov- ernment, which, although dropping the external pomp of ancient times, shall retain the dignity of which that pomp was the badge, and be rendered equit- able by being founded upon the will of the people. But although analogous, the two sci- ences cannot be said to go hand and hand, because they stand towards each other in the relationship of cause and effect. Architectural style is, indeed, but the effect of a series of causes, an examina- tion of whose influence upon its develop- ments would afford material for a volume. It is the outgrowth of religious sentiment, the necessary result of climatic peculi- arities and the type of government ; its characteristics being modified by a hun- dred causes, each of which is, in its way, a potential influence. OLEOGRAPHY. THE patterns which the Manufac- turers of Paper-Hangings have used, from the earliest time of that art, were put upon wood-blocks : and the designs, themselves, have been derived from the endless transformations of the Kaleidoscope. Numerous and beautiful were the devices produced, from time to time, in the progress of this most useful of the ornamental accessories of domestic archi- tecture. But, science is not satisfied. In fact, she never is, so long as there remains the slightest glimmer of a chance for another idea ; and here we have one more instance of the truth of this obser- vation, in the recent process for the utilization of cohesion figures. This interesting subject has been taken up by Dr. Moffat, of Glasgow, Scotland, and clearly shows that the well-known fact, of most kinds of oil, when poured on water, spreading over its surface, and sooner or later breaking into variegated patterns, which are often of very great beauty, and in this fact is likewise comprehended the greatest variety of forms or configurations. The scientific experiments of Dr. Moffat go to show, he tell us, that, from the construction of the oil film, we can determine the kind of oil examined, as also its genuine- ness. A drop of pure sperm oil, let fall on a vessel of water, quickly expands to several inches diameter, breaking up on the edge into numerous small holes. Sixtjr seconds is the time allowed, for such action, in the case of pure sperm oil. The centre of the patch is also found to have a great number of holes smaller than those on the edge. In two minutes' time the small holes begin to
