It

"DEAR SIR;- I have taken the liberty of writing “you on a subject of considerable importance. "is proposed to establish a British Association of 66 men of science similar to that which has existed "for eight years in Germany, and which is now "patronised by the most powerful Sovereigns of “that part of Europe. The arrangements for the "first meeting are in progress; and it is contem

plated that it shall be held in York, as the most "central city for the three kingdoms. My object "in writing you at present is to beg that you "would ascertain if York will furnish the accom“modation necessary for so large a meeting (which "may perhaps consist of above one hundred “individuals), if the Philosophical Society would "enter zealously into the plan, and if the Mayor "and influential persons in the town and in the

vicinity would be likely to promote its objects. "The principal object of the Society would be to "make the cultivators of science acquainted with "each other, to stimulate one another to new "exertions, and to bring the objects of science

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more before the public eye, and to take measures

Of the little band of four pilgrims from Scotland to York, not one now survives. Of the seven first Associates one more has gone over to the majority since the Association last met. Vernon Harcourt is no longer with us; but his influence remains ; a beneficent and surely therefore never dying influence. He was a Geologist and Chemist, a large-hearted lover of science, and an unwearied worker for its advancement. Brewster was the founder of the British Association; Vernon Harcourt was its law-giver. His code remains

to this day the law of the Association.

On the eleventh of May last Sir John Herschel died in the eightieth year of his age. The name of Herschel is a household word throughout Great Britain and Ireland—yes, and through the whole civilised world. We of this generation have, from our lessons of childhood upwards, learned to see in Herschel, father and son, a præsidium et dulce decus of the precious treasure of British scientific fame. When geography, astronomy, and the use of the

globes were still taught, even to poor children, as a pleasant and profitable sequel to “reading, writing, and arithmetic," which of us did not revere the great telescope of Sir William Herschel (one of the Hundred Wonders of the World), and learn. with delight, directly or indirectly from the charming pages of Sir John Herschel's book, about the sun and his spots, and the fiery tornadoes sweeping over his surface, and about the planets, and Jupiter's belts, and Saturn's rings, and the fixed stars with their proper motions, and the double stars, and coloured stars, and the nebulæ discovered by the great telescope? Of Sir John Herschel it may indeed be said, nil tetigit quod non ornavit.

With regard to Sir John Herschel's scientific work, on the present occasion I can but refer briefly to a few points which seem to me salient in his physical and mathematical writings. First, I remark that he has put forward, most instructively and profitably to his readers, the general theory of periodicity in dynamics, and has urged the practical utilising of it, especially in meteorology, by the harmonic analysis. It is purely by an application

of this principle and practical method, that the British Association's Committee on Tides has for the last four years been, and still is, working towards the solution of the grand problem proposed forty-eight years ago by Thomas Young in the following words ;

There is, indeed, little doubt that if we were provided with a sufficiently correct series of "minutely accurate observations on the Tides, "made not merely with a view to the times of low "and high water only, but rather to the heights "at the intermediate times, we might form, by "degrees, with the assistance of the theory con

tained in this article1 only, almost as perfect a "set of tables for the motions of the ocean as we "have already obtained for those of the celestial 'bodies, which are the more immediate objects of 'the attention of the practical astronomer.”

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Sir John Herschel's discovery of a right or lefthanded asymmetry in the outward form of crystals. such as quartz, which in their inner molecular

1 Young's; written in 1823 for the Supplement to the Encyclopædia Britannica.

structure possess the helicoidal rotational property in reference to the plane of polarisation of light is one of the notable points of meeting between Natural History and Natural Philosophy. His observations on "epipolic dispersion" gave Stokes the clue by which he was led to his great discovery of the change of periodic time experienced by light in falling on certain substances and being dispersively reflected from them. In respect to pure mathematics Sir John Herschel did more, I believe, than any other man to introduce into Britain the powerful methods and the valuable notation of modern analysis. A remarkable mode of symbolism had freshly appeared, I believe, in the works of Laplace, and possibly of other French mathematicians; it certainly appeared in Fourier but whether before or after Herschel's work I cannot say. With the French writers, however, this was rather a short method of writing formulæ than the analytical engine which it became in the hands of Herschel and British followers, especially Sylvester and Gregory (competitors with Green in the Cambridge Mathematical Tripos struggle of