It was known to the scientific world that several of the original thermometers, constructed by Mr Sheepshanks (in the course of his preparation of the National Standard of Length) by independent calibration of the bores, and independent determination of the freezing and boiling points on arbitrary graduations, were still preserved at the Royal Observatory.

Meanwhile as they walked she talked of flowers, of housekeeping; she discussed Marguerite's coming ball and Dent's brilliant graduation.

It was a delicate question, an affair of nuances, of almost imperceptible graduations; and in debating a matter of such nicety, a man must necessarily lay aside all petty irritation, such as being nettled by an irrational nickname, and approach the question with unbiased mind.

The lacy folds and furbelows and semi-transparencies that clothed her were now tinged with gold and now, as a hedge or a flower bed screened her from the level rays, were softened into multitudinous graduations of grays and mauves and violets.

[Footnote 4: Not that the transmutation of one species into another has yet been detected in any instance, or perhaps, even were it a fact, could be detected; but that such a serial graduation has been observed as might be commodiously explained by that supposition,and also by fifty others.]

Its interest lies in the accordance of the successive test values with the successive graduations of a true scale of sensitivity, in the ease with which the tests are applied, and the fact that the same principle can be made use of in testing the delicacy of smell and taste.