114 Application of the Microscope to the Art of Design. 



of the minute structure ; but A is far more suggestive for the 

 purposes of decorative art. It only requires reducing to strict 

 symmetry to supply an idea for an oriel window, a tesselated 

 pavement, or the centre of a plate. A slight change in 

 the angle of the illuminating pencil, coupled with an in- 

 crease of its brilliancy, produces a splendid effect at night. 

 The solid-looking rays shine with a lustre between that of 

 glass and gems, while the more transparent portions assume a 

 pearly or a silvery hue. In this state we have suggestions for 

 a star of an order of knighthood, or a superb brooch. With 

 the echinus spine, as with other objects adapted to our present 

 purpose, the decorative idea varies with the mode of illumina- 

 tion, and that which is best for artistic effect is not always the 

 most desirable for a scientific analysis of the structure. A com- 

 plete set of these experiments requires a good microscope, fur- 

 nished with a Lieberkuhn and dark cells, a side silver reflector 

 (which had better be on a separate stand), and the parabolic 

 illuminator, with all of which the object should be tried. It 

 is also imperative that the mirror under the stage should be 

 mounted upon an area capable of throwing it out of the per- 

 pendicular plane of the instrument, and that the aperture of the 

 stage should be large enough to admit light sufficiently oblique 

 to produce the effect of a dark ground. 



We may refer, in concluding these brief remarks, to the 

 compound polyps, and the polyzoa, so common on our coasts, 

 and which can scarcely be excelled in beauty when properly 

 shown. A small sketch of the Laomedea genimlata is given 

 in p. 131, vol. iii., of Recreative Science. When living, the ten- 

 tacles resembled pendants of frosted glass, 'the cells were clear 

 crystal goblets, and the stalks of a horny texture and colour. 

 From these polyps a clever designer could easily have devised 

 a pattern for an epergne, a portion of a border for a tesselated 

 pavement, or a figure for a sitting-room paper or a lady's 

 dress. The rational use of such objects cannot be attained by 

 mere imitation, but through the apprehension of a principle or 

 an idea, and its reproduction according to the purpose of the 

 manufacturer and the laws of decorative art. 



