Angles. What has been said more immediately applies to parallel perspective; so named from all the lines which intersect those running to the point of sight being parallel with the base line. When, however,a square or any cubical form is viewed at the angle, the two sides will not appear to vanish in the point of right, hut run to two points on the horizontal line, called vanishing-points; and this mode of treating the subject is called angular perspective. Now, these two points are always at an equal distance from each other, which is one - fourth of a circle, therefore, if one is determined upon, the other is easily found; for as one departs from the point of sight the other appears to approach it. as one may perceive by turning around sheet of paper, or a book, from a situation when ride is parallel with the base line until it it viewed upon the angles.

20.The oldl-fashioned silhouttes represented nothing hut the outlines of the picture, and yet they were very charming. This shows of how much Importance outlines are. Theirinfluence is felt in every picture. Every thinking artist who desires to reproduce luce an first studies its outlines. He allows his eye to glide over the lines, and tries to find the beauty of their curves. He follows the changes of the stronger and the weaker ones, the longer and the shorter, their windings and their easy combination. - DR.H. Vooel.

21. The cause of this may, perhaps, be more clearly explained by the following: Suppose the circle to represent the line of the horizon, which is the true representation of it when viewed out at sea, or where no obstructions intercept it, for then the water, coming in contact with the sky, presents a circular horizontal line. If a person, therefore, was placed at d, and looking to the point a, the line c would be parallel with the base, being at right angles with a, and consequently occupying one-fourth of a circle; but if he turned in the direction of b, then a and c would become vanishing-points, though still at equal distances upon the horizontal line, and would appear as in Fig. 6. In a panorama, which is a circular canvas viewed from the centre, this mode of measuring the various points is found to agree perfectly with the natural representation of objects.

22. Circles - If any one takes a drinking glass or cup in his hand, with the mouth of it towards him, and graducommencing a course of drawing from antique sculpture, it will be impossible to select what is beautiful in nature, or be able, to choose one point of view more interesting than another. It will also be impossible to combine a variety of object, unless we have a knowledge of those principles upon which the various work are constructed that have given satisfaction; for though, a* in the case with music, the varieties are endless, yet the is simple, ami to be perceived by those who investigate the arrangements of harmony. He who attempts to study from nature unassisted by education, in the first instance, will find himself often mistaken in his results; neither will he arrive at so expeditious a method of delineating objects with truth and feeling, as he will be continually in dread of falling into error. - John Burnet. 28. I do not hold it to be at all requisite that the photographer must be analytienl chemist, a profound physicist, or that he should be capable of solving the most intricate of the optician's problems; but I do maintain that be should have a general coro-prehension of all these sciences; that at least he may remark intelligently upon the accidental that occur in his working, and so profit by them. In fact, I am even one of those who uphold that the superior of a photograph can now be best attain.on to art and its principle.These must be studied with the same assiduity given to the understanding of the Chemicals.-John L.Gihon

Fig. 5.

21. Photography is a means to an end. By its aid we are enabled to secure representations of realities visible to the human eye. Pictorial art in photography consists in making such representations artistic and pleasing productions.

In what way should the student who wishes to excel in the art commence his practice? I will suppose him to have mastered the chemical and mechanical difficulties connected with photography through its first stages, and that his earnest endeavors for the future are to be devoted in acquiring a perfect mastery of the various subjects to be photographed. A knowledge of drawing is, if not essential, a most important requisite, proficiency in which will enable him to design a suitable arrangement for the sitter beforehand, whenever an important work may be required, thus taking a load off the mind when the actual moment arrives; such is frequently my practice when wishing to produce a picture out of the usual style. A continued method of noting in the mind the beauties of nature and art is valuable, the artist not allowing himself to pass quietly by any of the fleeting effects in nature, or to neglect any beautiful picture he may chance to see, without, arriving at a conclusion In his own mind as to what constituted the charms which have arrested his attention. He should learn to look on nature as if looking at a picture; this in time will have its effect, it persevered in by the student, in aiding the first step in art, which is the proper cultivation of the eye. A cultivated eye and taste will decide what forms to arrange, and also what light and shade to throw upon them. Practice alone can enable the student to equal his own ideas. It is a great thing to keep the judgment ahead of the practice, so that every succeeding work may present an improvement upon the last. - R. Slingsby.

22. Without the eye being made acquainted with the beauties of those who have advanced the art to its present state, either progressively, by studying the best works, or bv ally turns it from him, carefully watching all the elliptical forms until the brim becomes a straight Line in appearance he will have a correct idea of how it is that columns or other circular object assume to an oval shape at top or bottom,. according as they are above or below the eye. Or if he holds11»«cup with the side downwards and turns the month gradually round towards him, he will see why arches or circular gateways appear elliptical in a side view. It arises from parts of the circle being more foreshortened than other parts; that is to say. those lines which come more in the line of the visual rays.