48S 



DESICCATION. 



DESIGN. 



436 



heat acquired from the sun, in the northern regions of the country, is 

 so great, that though the air becomes cooler in the night, from the 

 absence of the solar radiation, the terrestrial radiation, as he observed, 

 is insufficient perceptibly to cool the ground, the heat of which 

 must therefore accumulate until the end of the solstice, and be the 

 immediate cause of the phenomena just noticed. Even at Adelaide, 

 in the province of South Australia, in a higher latitude, the tem- 

 perature, at the same season, is such as often to threaten, and 

 sometimes to produce, disastrous results ; that of the air having 

 been, for example, in February, 1858, for a week or more, at from 

 110 to 120Fahr. 



In South Africa analogous circumstances of weather and terrestrial 

 surface have been observed in Little Namaqualand, half of which is 

 stated to be a dreary waste of desert sand, and the remainder a howl- 

 ing wilderness of lofty rugged mountain chains and peaks, with 

 extensive tracts where no blade of grass or drop of water can be found. 

 Mr. Bell, a recent explorer, though he had travelled in South Africa 

 for twenty-four years, had never acquired, until his recent examina- 

 tion of this region, " any adequate idea of utter desolation." The 

 change of weather was' rapid from that accompanying heavy snow up 

 to intense heat ; indicating the agency, throughout the seasons, of the 

 same principles, which, as we have seen, govern the diurnal changes 

 of temperature in the deserts of Northern Africa. 



The principal desert-plains of America, being of a different character 

 and known by other names, as PAMPAS, SAVANNAHS, &c., are described 

 under their proper heads. 



DESICCATION is the operation of drying bodies, and is effected in 

 different modes according to the nature of the substance. 



One of the simplest cases is that of drying a precipitate which has 

 subsided in the fluid from which it is thrown down : this may be 

 effected after due washing by transferring it to a glass, porcelain, silver, 

 or platinum capsule, the weight of which being previously determined, 

 that of the substance dried is readily found on weighing. Sometimes 

 substances are dried merely by exposing them to the air ; in other 

 cases at a temperature regulated according to the nature of the sub- 

 stances, as at 100 or 212, in warm chambers, or a sand heat, or at a 

 red or white heat. 



The desiccation of precipitates upon paper filters is very commonly 

 effected to a certain extent by absorption, or by placing the filter and 

 its contents upon a piece of chalk or upon a brick ; the operation 

 being completed either by exposure to the air, or in any of the vessels 

 and at any of the temperatures above named. In many instances 

 desiccation is performed by means of the air-pump, which is useful in 

 those cases where delicate organic bodies, which would be injured even 

 by moderate degrees of heat, require drying. Mr. Leslie's process con- 

 sists in placing the substance to be dried (or a fluid to be evaporated) 

 under the receiver of an air-pump, over a basin containing sulphuric 

 acid or some other substance having great affinity for water. The 

 receiver being exhausted, the operation is left to itself. On account of 

 the absence of the air, the moisture is readily vaporised and is quickly 

 absorbed by the sulphuric acid ; and the vaporisation and absorption 

 continue till the substance is dry. 



Desiccation may be carried on at common temperatures without the 

 process of exhaustion above described ; thus a basin containing quick- 

 lime with a moist precipitate placed above it, and the whole covered 

 with a jar or receiver, will soon render the precipitate dry. Any deli- 

 quescent salt may be substituted in some cases for sulphuric acid or 

 quick-lime ; such, for example, as potash, carbonate of potash, and 

 chloride of calcium. 



In chemical investigations it is frequently necessary to deprive 

 gaseous bodies of their moisture. The nature of the drying substance 

 employed must depend upon that of the gas to be desiccated : thus 

 ammoniacal gas is absorbed by chloride of calcium, and immediately by 

 sulphuric acid, but potash or carbonate of potash answers well for it. 

 Again, sulphurous acid gas would be absorbed by potash or carbonate 

 of potash, carbonic acid being evolved in the latter case. In fact care 

 must be taken that the desiccator exerts no chemical action upon the 

 substance to be dried. 



DESIGN. In the Fine Arts the word design (from the Italian 

 ditcgnare, to draw) is employed in two very different significations. 

 In the first place it is used merely to signify the act of drawing, or 

 representing in lines, the form of any object; in the next place it 

 expresses that combination of invention and purpose which enables the 

 artist to compose a picture or a group, without reference to the material 

 in which H is executed. 



The accurate conception of form and beauty is displayed in the most 

 masterly degree in the ancient Greek sculptures ; and in the invention 

 of appropriate attitudes, and perfection of physical form, the design of 

 the best Greek sculptors cannot be surpassed. And whilst such works 

 as the marbles of the Parthenon are the safest guides to the young 

 sculptor, they afford also models that cannot be too carefully considered 

 by student* of every other branch of art. Of all the existing specimens 

 of painting, the works of the Italian masters display the most consum- 

 mate excellence in design, especially the Florentine and Roman schools, 

 and among them Raffaelle's in particular. The conception of the story, 

 and the ruling passion of the moment ; the selection of forms appro- 

 priate to the actors of the story; the invention of appropriate attitudes, 

 not merely for the single figures, but for whole groups, artfully dis- 



posed in such manner as to be adapted at once to the freedom of nature 

 and the intention of the artist to assigu to each its position according 

 to its prominence in the story; and the perfect execution of the design, 

 placing before our eyes in a palpable shape the inward thoughts of the 

 painter, combine to render the design of Raffaelle's works the most 

 perfect in existence. Michel Angelo's power is more apparent in the 

 conception and execution of forms purely physical, and his design is 

 therefore of a more limited though perhaps hardly less elevated style. 

 A single figure from his unrivalled hand may be contemplated with 

 emotions of admiration and wonder scarcely less than those which we 

 feel when the whole of his greatest work is before us. Raffaelle 

 designed not merely to overawe the spectator with physical vastness, 

 but to elevate him above the visible world. Human suffering, super- 

 human inspiration, and divine benignity are subjects within the reach 

 of his pencil. These are displayed equally in his cartoons as in 

 his frescoes and oil paintings perhaps, indeed, even more. [CAR- 

 TOONS.] The tortured figure of the chastised Ananias, the terrible 

 power inspired into Peter, the prophetic absorption of the apostle near 

 him, pointing with his finger to the source of that power, bring into 

 the design of that one cartoon (the Death of Ananias) the most sublime 

 speculations ; and if it be second to the Transfiguration as a picture, it 

 is no less a model of perfection in design, notwithstanding anachronisms 

 of costume, &c., which it would be absurd in a painter of the present 

 day to repeat. 



The student in design may discover the means by which former 

 artists attained their power by carefully studying and thoroughly ana- 

 lysing then- works, namely, the sculptures of Greece and the paintings 

 of the old masters. But it must be study pursued with a view to 

 the enlargement of his artistic powers, not to the accumulation of pre- 

 cedents or the imitation of style. Copying, he must recollect, is at 

 best, as Reynolds expressed it, a delusive kind of industry. He must, 

 however, equally avoid following the implied advice of Reynolds, merely 

 to store his mind with the thoughts of the great masters, and give them 

 forth second-hand as his own. That the greatest poets and painters 

 have borrowed is no apology for an education which recommends 

 only borrowing. To appropriate with justice and effect the thought of 

 another, the borrower must be at least as great as the original inventor. 

 The legitimate object of study, or that part of study which seeks to 

 shorten the process of education, is to discover the mode which other 

 artists have pursued in disciplining their minds, and eyes, and hands, 

 in order to comprehend and express the nature which they had to 

 portray. Art, as has been said already [ARTS, FINE], is creative, not 

 imitative. Every work of Fine Art, to whatever class it belong, is 

 valuable in proportion as it reveals the inner thought, idea, or mental 

 idiosyncracy of the artist ; and that course of study, therefore, will 

 be most efficient which prepares the student to give the fullest 

 effect to what he himself has observed in human experience and 

 external nature. The study of the best poets, of histories, and the 

 lives of individuals, of emotions casually displayed in the events of 

 daily life, and in fact everything that helps to teach a knowledge of 

 human nature, and the working of its internal feelings, combined with 

 an accurate knowledge of those external forms which must enter into 

 every composition, will conduce to the development of a power of 

 original design. 



DESIGN, IN ARCHITECTURE. Design, together with its 

 meaning of drawing, is often understood to mean the idea, rather than 

 the drawing, of either a picture or of a building ; and people talk of the 

 design of either of those classes of art production, as though it meant 

 exclusively the abstract invention, or the original conception, of the 

 artist. There is also a moral sense attached to the word, which is 

 frequently used, in works even which treat exclusively of art, namely, 

 the sense of intention ; and a man is said to do a particular thing with 

 design, when he does it with a premeditated intention. In the follow- 

 ing notice the word will be used exclusively in the primary sense, or 

 that of an equivalent to the art of drawing, as applied to archi- 

 tecture or engineering ; the secondary sense will be referred to here- 

 after under the head INVENTION ; and the illustrations to be given will 

 have special reference to the practice of engineering and architectural 

 works. 



The scheme, idea, or, as it is more usually termed, the design, 

 whether for an intended building or that of one already erected, is 

 usually shown by means of a series of diagrams or drawings, which, 

 being exact geometrical representations, are therefore too technical 

 and formal to satisfy those who look at them as pictures, besides being 

 likewise in some degree imperfect as separate representations, yet, 

 taken one with another, convey a much more exact and complete 

 notion of the whole, both internally and externally, than can be 

 obtained by any other mode of delineation ; because they not only 

 exhibit the actual forms and dimensions as they really are intended to 

 exist, and not merely as they would appear to the eye according to the 

 situation of the spectator ; but they also reveal the whole anatomy of 

 the fabric, together with many particulars that are concealed from 

 view in the edifice. Such drawings consist of plan, eleration, and sec- 

 tiiM, besides other detailt, or parts at larf/e ; and their number will 

 depend either upon the nature of the building, that is, on its being 

 more or less complex, or as it is intended to show it more or less 

 fully. 



Although a certain prejudice exists against such drawings, on the 



