the other coarse and blunted. Dr. Mahomed was a very promising physician, on the eve of becoming well known, when he caught a fever of the same description, I am told, as that on which he had become an authority, and died of it in his newly purchased house.

I could not make good composites of lunatics; their features are apt to be so irregular in different ways that it was impossible to blend them. I took a photographer with me to Hanwell, where it was arranged that the patients should sit two at a time on a bench. One of them was to be led forward and posted in front of the camera, while his place on the bench was filled by the second patient moving up into it, whose previous place was to be occupied by a third patient. It happened that the second of the pair who were the first to occupy the bench considered himself to be a very mighty man, I forget whom, but let us say Alexander the Great. He boiled with internal fury at not being given precedence, and when the photographer had his head well under the velvet cloth, with his body bent, in the familiar attitude of photographers while focusing, Alexander the Great slid swiftly to his rear and administered a really good bite to the unprotected hinder end of the poor photographer, whose scared face emerging from under the velvet cloth rises vividly in my memory as I write this. The photographer guarded his rear afterwards by posting himself in a corner of the room.

Many years later, I tried to perform the exact opposite to composite photography, namely, to annul all that was typical in a portrait and to preserve its peculiarities. I called it “Analytical Photography,” and explained it in _Nature_, 1900, and in the _Photo. Soc. Jour._, 1900-1901. It depends on the fact that a positive and a negative glass plate, _both in half or still fainter tones_, when held face to face neutralise the peculiarities of one another, so the effect of their combination is to produce a uniform grey. My plan was to fix a _negative_ composite in front of a _positive_ portrait of one of its elements, all in half tones, with the result that the composite abstracted all the typical portion of the portrait while its peculiarities were isolated and remained. “Alice in Wonderland” would have described it as the “grin without the Cheshire Cat.” I succeeded, but the result did not give an intelligible idea of the peculiarities, the non-essentials being as strongly marked as the essentials, and the whole making a jumble; so I went no farther with this process.

In 1882 I published an illustrated memoir in _Nature_ on the conventional way in which artists had hitherto represented a galloping horse. Mr. Muybridge had, by means of beautiful photographs of twenty momentary successive attitudes, recently shown, beyond possibility of cavil, that the conventional representation was totally untrue to fact. I asked myself the question why observant artists had agreed for so long a time in drawing galloping horses with their four legs extended simultaneously, and why their representation had never been objected to. It occurred to me that composites of successive attitudes that were too momentary to be distinguished might answer the question, which it did. When all of the twenty attitudes are combined in a single picture, the result is certainly suggestive of the conventional representation, though in a very confused way. Then, finding by my own observation that it was difficult to watch all four legs at the same time, also seeing that according to the photographs of Mr. Muybridge, the two fore legs were extended during one quarter of a complete motion, and that during another quarter the two hind legs were similarly extended, I made composites of these groups separately. Then, cutting them in half and uniting the front half of the former to the hind half of the latter, a very fair equivalent was obtained to the conventional attitude. I inferred that the brain ignored one-half of all it saw in the gallop, as too confused to be noticed; that it divided the other half in two parts, each alike in one particular, and combined the two halves into a monstrous whole.

This is a convenient place to speak of the method of stereoscopic maps, which I devised so long ago as 1863. It was published together with specimens made for me by my cousin, long since dead, R. Cameron Galton, in the _Proceedings_ of the Royal Geographical Society[18] of that year. I cannot fully understand why stereoscopes do not hold a higher position in popular estimation than they do; it may be partly due to two causes—to the fact that the two eyes are unequally operative in a larger proportion of persons than might be supposed, and to the cost and unwieldiness of the usual stereoscope. Compound lenses give better and wider images than plain ones, but for common purposes I find that plain ones, mounted as in an eyeglass, serve quite well enough. Those I generally use are cheap things, mounted in a strip of wood.

I wished to obtain a map that should have the effect of a model, so suitable models were procured and photographed stereoscopically. The result was a perfect success. An unexpected result occurred when a pure white plaster cast was treated in this way, for it wholly failed to give the required appearance of a solid, but if grains of dust were sprinkled over it, much more if names were written on it, the stereoscopic effect appeared in its full strength. Good models, and therefore stereoscopic maps made from them, give a far better idea of a mountainous country than any ordinary map can do, however cleverly it may be shaded. Map-makers might well pay some attention to stereoscopic maps and to providing cheap eyeglasses with which to view them.