Again, if a straight line crossing a contoured map represents a railway, and its end levels are those of the ground itself, and it is evenly graded from end to end.

The figures above the line are those of the ground contours.

By comparing the figures at any point above and below the RULE 7. line, we can at once see whether that point on the graded line is above or below the ground, i.e., whether it is embankment or cutting. We thus get the outline in plan of the top edge of the cuttings and of the foot of the embankments, also the position and length of tunnels.

Incidentally, this method of grading a straight line between RULE 8. two end points would settle the question of where the intervening crest (referred to in IV.) lay-if it were a visibility question as any portion of the straight line which goes underground means a convexity. The point of greatest disparity is then the crest in question.

The map which accompanies this paper may supply a few questions for practice as illustrations of V. and of the subject generally, in addition to those already given, 1-8.

Q. 9. Between a straight line running E. and W. 100 yards N. of Wyke reservoir and another running W. from Radipole Church indicate by shading all the ground unseen from contour 225 (No. 9).

1

Q. 10. Trace a road max. gradient from Wyke reservoir to join the Chickerell Road and another from W. Chickerell, same ruling gradient over the col S.W. of Buckland Ripers to join the Abbotsbury Road.

Q. 11. Trace a railway from contour below Radipole Church, going under Wyke ridge, and joining the existing railway near the Torpedo Works, showing by hachures the embankments, cuttings, and tunnel exits.

Q. 12. From the Breakwater Fort-level of eye 25 feet-show the crest (or skyline) on the map surface throughout.

All these exercises could be done on tracing paper to which the contours may have been transferred.

The foregoing notes, as well as the map, are the result of carrying on instruction in military sketching over the ground pourtrayed.

This instruction is, of course, an important part of military education, and, to those who have an aptitude for the work (the cases are more or less exceptional), it is an extremely interesting part.

There is no reason, however, why the subject, at least to the extent of map reading, should be confined to military students or surveyors.

It is quite within the grasp of the educated and intelligent student of nature.

The Seeing Power of Beasts and

Birds.

By H. J. MOULE, M.A.

O speak of a failure in the eyesight of wild animals

sounds like a token of lunacy.
hearer would say

66

What!"-the "What! As if any man's eyes are equal in keenness to those of every beast and bird! What nonsense to talk of a failure of any kind in their eyesight! The man must be a lunatic!" Just so, and yet, "greatly

daring," the writer wishes to bring before the club that very idea. His puzzle is to understand why some beasts and birds appear not to see a man although in full view, if he is stock still. The fact is undoubted. Most likely every one here could speak of instances witnessed by himself. To the writer this experience has perhaps come more often than to some others, for he is much given to solitary sketching. Now, when you are standing or sitting, quite still, with a sketchbook in use, and in a quiet field or wood, you have a rare chance of seeing more things than the landscape and your attempted pourtrayal thereof. The glimpses of the manners and customs of some beasts and birds which thus come to you are quite unspeakably charming and interesting. A few of such glimpses

which have fallen to the lot of the writer, always as a sketcher, may be rehearsed.

While he was sketching by the stream-side in Frome Billet Down, West Stafford, two kingfishers thought the best place for a free fight was within a dozen feet at most of the wholly unperceived sketcher. It was an astonishing sight to behold those two birds darting and dodging about in the air, flashing like jewels as the sun's rays caught them at all sorts of angles, and most viciously prodding at each other with their long bills. The battle went on for about two minutes, but without bloodshed, as far as could be seen.

Another time a sketch was going on quite near Dorchester, at the entrance of Slyer's Lane. There is an iron bar crossing a little watercourse which was being sketched. The bar was certainly not ten feet from the sketcher. Presently there was a blue flash, and a kingfisher perched on the bar. He preened himself a bit, sharpened his bill on the said bar, looked about quite happily, and wholly without view of the sketcher. Then he flew on up stream in blissful ignorance of the nearness of his supposed natural enemy. Presently his place was taken by a thrush of equally unperceiving mind.

Another time, at Mr. Floyer's beautiful river-side, the Allers, West Stafford, a sketch was begun, carried out, and ended on one side of a bush while, as it seemed, a heron was all along on the other side watching for fish. At all events, on the sketcher moving, up got the heron from within a very few feet. He was in a terrible fluster, and flapped away at his utmost pace. Yet he had never seen the sketcher till he moved. So much for unperceiving birds.

As to beasts-that is, small ones-it is a thing that has repeatedly happened that mice of more sorts than one have disported themselves in peace of mind close to the writer while sketching. This occurred, for instance, quite lately. He was doing a "bit" in a barley field of Mr. Hayne's during last harvest. There was a rustle in the stubble. "A mouse," thought the sketcher. The next moment the mouse ran against

his foot. "Dear me! that stone wasn't here yesterday," the little animal seemed to say to itself. It turned away quite quietly, and moved on calmly hunting for scattered barley corns. The beauty of its lithe movements, seen at three feet or so from the eye, and of its lovely red coat contrasted with the pale barley-straw colour and green stubble-plants, was a sight worth beholding.

A few days before this another pretty thing of the sort happened. The writer had been sketching by the south-west corner of Yellowham Wood, and was walking down the heath track to Higher Bockhampton. Presently a white-tailed squirrel appeared about twenty yards away. He was steadily galloping up the white sandy path, most likely returning from a raid in Mrs. Hardy's garden. The writer stood stock still. On galloped the squirrel. At about ten feet off it stopped and looked about; seemed, too, to sniff and listen, but clearly did not see the foe, for it started again quite steadily, passed the writer's feet within a very few inches, and, without the slightest hurry, galloped on towards Yellowham Wood, where doubtless was its abode.

But the most interesting of these near glimpses of our timorous four-footed neighbours is that which will now end this rehearsal.

On a February day a few years ago the writer was sitting by the Stratton roadside, sketching a bit of the snowy West Ward with Burton Mill in the background. He was close over a culvert which leads water under the road into a large pool about two hundred yards beyond the first bridge, on the right or east side of the road. In the strong stream from the culvert, only eight or nine feet from the sketcher, was a mass of water crowfoot in its early matchless green and waving with its wonderful grace. Presently came a water vole, strenuously swimming up stream. It gave swift snaps at the water crowfoot. This action at first the writer could not understand. But the vole explained himself. The first snaps were failures, caused seemingly by the strong stream making it hard for him to take a