1839.] Stained Glass from the Old Authorities. 585 uniformity, be governed by that of the dwelling to which they are to be at- tached. The materials, of which they are con- structed, are either wood or iron ; and the comparative merits of both of these have been the subject of much diversity of opinion, among men of experience and practice. Especially in the use of iron for the roof, there is admitted to be great risk of the expansion and con- traction of the metal, from the extremes of our climate causing apertures be- tween the rafters and lights, admitting the external air, and, of course, adding to the cost and difficulty of properly heating. Notwithstanding, however, this and other objections, such as, for instance, that an iron-roofed structure is much more difficult to warm, than a wooden one, the great convenience of iron, and the extreme lightness and elegance it imparts to the construction, will always give it a signal advantage over wood. Conservatories, on a large scale, are becoming more and more popular, each year, amongst our wealthier citizens ; and we know some of considerable pretensions ; but we have not reached the magnificent proportions, in such structures, to be found in Europe. However, we are yet young; and our hope ardent ; so that, with the laudable ambition of our nation, there is a pros- pect of future magnificence rising before us, which it is our duty to cherish to the utmost. STAINED GLASS. FROM THE OLD AUTHORITIES. No. 2. THE MATERIALS. IN a preceding number, we gave, for reasons therein explained, the His- tory and General Method of the Earliest Processes in Stained Glass. We now set forth a Detail of the Modes of the Stained Glass Artist-Chemists of the Middle Ages. Doubtless, present artists in glass will smile at some of the sagely enforced prescriptions exposed below ; but, still, as these emanate from a por- tion of the old literature of the subject, which, perchance, they may not have read, they might be interested in the groping steps and darkling progress of their earnest brethren of the olden time. If we are not greatly mistaken, the cele- brated Leonardo da Vinci constantly used some human being, as a model for his creations of fancy, often depicting the face of a lovely young woman from the time-scarred features of an ugly old man. Following this practice, of taking models for deviation, even this buried rubbish-lore of the art may give an im- portant hint to the modern artist in glass. The Materials. The Materials necessary for coloring glass are the sparks or scales of iron, which fall from the anvils of blacksmiths when they forge ; white saud, or silicious earth, or, what when comminuted are the same, the little flints of a clear river ; red lead; saltpetre; rocaiile — a name for the little, round, green and yellow grains, sold by the tradesmen; silver: harderic, or Spanish iron ore — artificial- ly produced with filings of iron and sul- phur, stratified in a covered crucible, then to be taken out, and put into the fire for five or six hours ; — manganese, saffre, or zaffre — a gray mineral earth, which colors glass and gives a blue color, fit for enamel, the name arising from the fact that it gives the color of the sap-
