a dark intermediate space, are worthless blades, (A). Many others are extremely crooked. All the looping and intertwining here exhibited, takes place within an area not larger than the head of a pin. It is almost indistinguishable by the eye unassisted, but if cotton from a bad sample be brushed out till it seems ever so even, under the microscope its deficiency in straightness will be very obvious.

Photo. No. 9. A knot of worthless fibres, (A) and (E) or (F); occasioned, probably, by a tendency to twist in fibres too weak to preserve their longitudinal position during the process of ginning.

Photo. No. 10 has been already described.

Photo. No. 11. The fibre 1, 1', which is a (G) fibre, is highly interesting on account of its great resemblance to the fibres shown in Photo. No. 10. The apparent crossing of the spiral fibrillæ is an effect due to the transparency of the fibre. The same fibre occurs, though very rarely, in cotton from Brazil. It may possibly be an instance of reversion, as some branch of an apple-tree might bear a crab, or a pigeon of a highly cultivated fancy breed might show a feather resembling the plumage of the original Blue Rock.

I am constrained to express my admiration of this illustration as a highly successful achievement in photo-micrography.

Photo. No. 12. The end of a (C) fibre, broken under a strain of 110 grains.