"Sometimes valuable color notes are to be had in crowded buildings where it is not convenient to sit down and make a large study. For such cases a small pocket water-color block will be very useful. There is a small vest-pocket water-color box carrying six colors, which may be set over the thumb, a water-bottle attached, and with it one can stand unobserved in a corner and get color notes which otherwise must be passed by. In studying fresco painting, tempera is very useful. It is mixed up with water and applied to paper, but may be worked over in the manner of oils,--a great advantage in making studies. "The _chambre eclaire_ is invaluable as an aid to drawing, in blocking out water-colors. It will enable one to make a drawing in an hour which otherwise would require all day. It is an instrument little known outside of Paris, but is much in use there among architects. It consists of a prism mounted on a telescoping leg which may be fastened to the drawing-board. The eye looks through the prism and sees the building reflected on the paper; all that remains to do is to trace this outline. It does not teach one to draw, but it does save time, and produces better drawings than can be made without it. The best place to buy them is of Cevalier, on the Seine, near the Pont Netif, Paris. Only those with the best prisms are of any use: such a one, with two adjustments only, can be had for sixty-five francs. The table which is necessary for its use costs fifteen francs additional; that is, a total cost of sixteen dollars. In buying a table, be sure and get one with sliding legs which can be taken off the head and packed flat. "One of the very best ways to study, and one which has very direct tangible results, is by the aid of printed plates. Take such a book as Letarouilly's _Edifices de Rome Moderne_. Go to the buildings themselves and compare the drawing with the building; see what drawings on paper really mean when executed; mark up the plate; note the proportion of masses, the size of ornament, the relative proportion of openings, and wall spaces, the effect of color and texture, and the use of material. Make suggestions for better ornament, proportion, etc., and then go home and make a new design with all the improvements you have noted. "The reverse of this method is, to sit down in front of the building with T-square and triangle and translate the perspective building back on to paper in elevation. [Illustration: XIV. Detail of the Principal Doorway to the Basilica at Altamura, Italy.]