Royal Institution of Great Britain. 127 



rately and unmixed, each separate colour being firmly fixed in the 

 paper, by washing it plentifully with water till the water runs off 

 clear, so that there is no danger of one colour tarnishing another by 

 mixing with it ; by this means the colours are so pure that he is not 

 under the necessity of using those that are not permanent, for the 

 sake of their brilliancy, as it is well known that a transparent colour 

 used over another produces a much brighter third colour than when 

 the same two colours are mingled (his colours are prepared in the 

 usual way). When he has got his picture to the utmost degree of 

 force that he is able by these processes, he varnishes it over in the 

 early stages with a solution of gum tragacanth, and in the latter 

 with a solution of isinglass in alcohol, painting over these and again 

 varnishing, till he produces a depth of colour equal to the most 

 powerful oil picture. By these means colours that, although per- 

 manent in themselves, may injure other colours (permanent sepa- 

 rately) by their chemical agency, become protected from each other, 

 and all are defended from the action of gases and vapours, as well as 

 from injury by smoke, grease, or dirt; for the latter may, with the 

 greatest facility, be removed by spirit of wine, which readily dissolves 

 them, while it cannot injure, even in the slightest degree, the surface 

 of the picture : for since isinglass can only be dissolved in spirit of 

 wine, by being kept at the boiling point for several hours, it is evi- 

 dent that when used in a cold state it cannot affect the varnish. To 

 defend the picture from injury by humidity, it may be varnished by 

 any of the varnishes used for oil pictures, which may all be taken off 

 again readily by alcohol, down to the exact surface of the picture. 

 Nay, if the whole surface were painted over with oil paint and suf- 

 fered to dry, it might be as easily cleaned. Amongst those present 

 were the president and several members of the Royal Academy, who 

 expressed the greatest interest in Mr. Robertson's principles and 

 details. 



May 27th. Mr. Brittori's remarks cm, and illustrations of, the 

 Old Domestic Architecture of England. This subject was illus- 

 trated by a variety of curious prints, drawings, and models, tracing 

 the progress of the art, from the Norman style still extant in some 

 of our ancient buildings, down to the period when Roman architec- 

 ture began to be mingled with our national works, and till it ulti- 

 mately supplanted them in the buildings destined for domestic use, 

 as well as those intended for divine worship. The new buildings at 

 Windsor Castle, and those in and about London, were very particu- 

 larly dwelt upon, as indications of the present state of domestic 

 architecture. 



Numerous presents were placed on the library table, given by 

 G. Bennet, Esq. They were principally from the South-Sea Islands. 



