which still farther illustrated the mental action in certain optical phenomena. An article in the "Edinburgh Review" of October 1858, describes thus the effect of the Pseudoscope :-" When an observer looks with it at the interior of a cup or basin, he not unfrequently sees it at first in the real form, but by prolonging his gaze, he will perceive the conversion within a few minutes; and it is curious, that while this seems to take place quite suddenly with some individuals, as if the basin were flexible and were suddenly turned inside out, it occurs more gradually with others, the concavity slowly giving place to flatness, and the flatness gradually rising into convexity."*

Wheatstone was exceedingly interested in this discovery of the interference of mental action with optical phenomena, and invented several instruments with the view of ascertaining the principles ou which it depended. The subject led him to study the subject of nervous organisation; but it is believed, that he effected no special discoveries in that field.

In 1834 the science of Electricity began to occupy Wheatstone's attention. He endeavoured to ascertain the velocity of the electrical current. He invented many most ingenious machines with that view. He seems to have made only an approximation to the truth, viz., that the current travelled through a mile of wire in less than the 360th part of a minute.

It now occurred to him that electricity might be employed in conveying intelligence along great distances by moving a magnet. By this time an idea of the same kind had occurred in Germany. Mr Cooke, when there, had become informed of the investigations by Schilling, and having come to London, made these known to Wheatstone. A proposal for a partnership between the two, was suggested, and was carried out. Messrs Cooke and Wheatstone

A curious circumstance, analogous to the phenomena here described, was, without the help of any instrument, observed by me and other friends lately, in watching the revolutions of a cup anemometer on the top of Alnwick Castle. On looking at the instrument, it was seen revolving in a direction consisting with the truth; but on continuing to look at it, in about half a minute the anemometer suddenly appeared to change the direction of its rotation, and to continue so to rotate. We remained for some time looking at the instrument to repeat the experiment. The same result on every occasion followed, and to every one of the party, eight or nine in number.

soon thereafter were employed to establish electric telegraphs on most of the great English railways.

In 1837 the five-needle telegraph was invented; in 1840, the alphabet dial telegraph; in 1841, the type-printing telegraph; and the automatic telegraph between 1858 and 1867. By this last machine it was found possible to transmit words at the rate of from 100 to 160 words per minute.

In 1840 Wheatstone conceived the idea of a submarine telegraph cable, and pointed out both the difficulties and the means of obviating them.

His last work was to contrive a new recording instrument for submarine cables, formed by a globule of mercury moving to and fro in a capillary tube containing acid, or by a drop of acid in a tube containing mercury, and which was found to be 58 times more sensitive than any recorder previously employed. He had gone to Paris to exhibit this invention to his colleagues of the Academy of Science, when he was attacked by the fatal illness-bronchitiswhich terminated in his death.

This brief notice of Wheatstone's discoveries in the science of sound, optics, and electricity gives but a poor idea of the immense amount of brain work which he went through in the long life accorded to him. The papers which he contributed to Societies both in Great Britain and on the Continent are very numerous. They were always characterised by great lucidity of style and by copious and telling illustrations, which made them both attractive and instructive.

Wheatstone was elected a Fellow of the London Royal Society in 1836, a Chevalier of the Legion of Honour in 1855, a Foreign Member of the French Institute in 1873. In 1868 the Government of Lord Derby conferred on him a knighthood.

In private life Sir Charles Wheatstone had the reputation of being reticent and unsociable. The fact probably was, that his mind was constantly absorbed with the problems which were constantly presented to it. He was so nervous and bashful, that though always ready and pleased to describe his discoveries to any single individual, he entirely broke down when he attempted to address an audience. Hence, his Professorship of Natural Philo

sophy in King's College, London, was little better than a title; for he never had a class..

There was no physicist of his time so universally respected. His remains were brought from Paris for interment in the family burial place at Kensal Green. The procession was followed by a vast number of carriages, including many of the nobility; and even the shops in the streets along which the funeral cortege passed were shut, whenever it was known whose it was.

DAVID AITKEN, D.D., who had been seven years an Ordinary Fellow of this Society, was born about the beginning of this century. He died on the 27th March last, in his own house in Charlotte Square, Edinburgh. He was educated at the High School and University of Edinburgh, and became a licentiate of the Church of Scotland.

I believe that he had been tutor in the family of the Earl of Minto, by whom, or through whose influence, be was in the year 1829, presented to the parish of Minto. There he remained minister for thirty-seven years; and on resigning his charge, purchased a house in Edinburgh, where he lived till his death.

Being fond of travel, he visited Norway, Italy, Egypt, and Syria. As he suffered extremely during the winter season from delicacy of chest, he often spent the winter abroad. Possessing an independent fortune, he was able to obtain the services of an assistant during his absence.

He was a person of literary tastes, was well acquainted with the German language, and was a friend and correspondent of the German philosopher Hegel. In the year 1827 he wrote an article in the " Edinburgh Review" on German literature. He also drew up the Statistical Accounts of Minto Parish, embodying an excellent account of its geology, botany, and zoology.

His knowledge of Church history was so considerable that he was offered the Chair of Church History in the University of Edinburgh. On his declining it, the late Dr Welsh was appointed. His sermons were in composition marked by great elegance and clearness; but owing to delicacy of chest, his voice was weak, and his manner in the pulpit had not the earnestness necessary to create interest.

He was exceedingly fond of natural history, and took great

interest in his garden, which was always kept with scrupulous

neatness.

JOHN HUGHES BENNETT was born in London 31st August 1812, and died at Norwich 25th Sept. 1875. He had joined our Society in 1842.

He was educated at the Grammar School, Exeter. It is stated, however, that he was indebted for the early part of his education to his mother, a lady of brilliant intellectual attainments. Being a great admirer of Shakespeare, she caused her son to read aloud to her many of his plays, and as he did so, taught him the art of emphasis and rhetorical action. Probably to this tuition of his mother, Dr Bennett was indebted for the elegance of his composition, and for the impressiveness of his delivery when he lectured or spoke in public.

He commenced the study of medicine at Maidstone, in the year 1829, under the guidance of a practitioner there. It was there that he acquired the art of dispensing, and even obtained a certain amount of medical practice. He assisted also in post-mortem examinations.

To acquire better medical instruction and training, he removed to Edinburgh in the year 1833,-unacquainted with any one in that city or in Scotland. By his talents and assiduity he soon attracted the notice of his professors, and obtained the esteem of numerous fellow-students. His attention was devoted chiefly

to anatomy, physiology, and pathology. Having joined the Royal Medical Society, and shown his abilities and knowledge at its meetings, he ultimately became President of the Society. Whilst still a student, in the year 1836, he published two papers which obtained for him considerable credit.

In the year 1837, he received the degree of M.D. with the highest honours, obtaining at the same time a gold medal for his thesis.

After obtaining all the knowledge which Edinburgh could supply, Dr Bennett repaired to Paris, where he studied for two years. Being able to speak and write the French language fluently, he wrote in the French medical journals, and ultimately became President of the Parisian Medical Society.

He also went to Germany, spending some time in the principal University cities, and endeavouring to acquire knowledge beyond what he had already obtained. One of his acquisitions on the Continent was ability to use the microscope in practical medicine. Nor was his pen idle, for whilst abroad, he contributed no less than seventeen articles to Tweedie's "Library of Medicine."

In 1841 he returned to Edinburgh, and commenced a course of lectures on histology. He there took the opportunity of showing to what an extent the microscope might and should be used. It was at this time that Dr Bennett published a treatise on the use of cod-liver oil as a therapeutic agent in certain forms of gout, rheumatism, and scrofula,-dedicating the treatise to Sir Robert Christison. In Germany he had seen the good effects of using this medicine in these cases.

From 1842 to 1848 he continued to give lectures on various medical subjects. In the last named year he was appointed to the Chair of Institutes of Medicine, vacant by the transference of Dr Allen Thomson to Glasgow.

For several years Dr Bennett was proprietor and editor of the Edinburgh Monthly Journal of Medical Science," in which, besides editorial articles and reviews, he inserted multitudes of separate memoirs.

In the "British Medical Journal," where a detailed account of Bennett's life and labours is given, and from which I have culled the foregoing notices, I see a list of no less than 105 memoirs on various anatomical and pathological subjects.

In July 1848 Dr Bennett was unanimously elected to the Chair of Institutes of Medicine.

Whilst teaching in the University and in the Infirmary, Professor Bennett found time for literary work, and published his highly appreciated "Clinical Lectures on the Principles and Practice of Medicine." This book passed through five editions in this country, and six in the United States, besides being translated into French, Russian, and Hindoo.

The following additional works flowed from his ready pen. Their titles were, "Pulmonary Consumption," "Cancerous and Cancroid Growths," Introduction to Clinical Medicine," "Outlines