100 MONTHLY SUMMARY 



of the tesserse and the encaustic tiles have since taken place. 

 The latter were made into forms of clay of about sk inches 

 square, into tlie surface of which, while still in a soft state, were 

 pressed metal dies upon which a pattern was worked in relief; 

 the ornament being thus indented, the intaglio or indentation 

 Avas filled up with different coloured clays whilst in a liquid or 

 •*slip" state. The tile was then baked and "covered with a 

 vitreous glaze, at once enhancing and protecting the colour of 

 the material. The great difficulty which was experienced arose 

 from the different kinds of clay not amalgamating so as to con- 

 tract equally in the oven. It was Messrs. Minton who took out 

 the first patent for the manufacture of these tiles, and it was 

 they who by long-continued perseverance and costly experiments 

 at last succeeded in conquering this difficulty, and producing the 

 tiles in the perfection in which they are now manufactured. 



The tesserae, or plain tiles, have also proceeded through many 

 difficulties towards perfection. The first improvement was to 

 place compact and. well-manipulated clay in a machine from 

 which it was compelled by great pressure to exude through a 

 small horizontal aperture, where it was cut into lengths as it 

 appeared. The plan adopted by Messrs. Minton for the manu- 

 facture of tesserae, such as those in this pavement, was discovered 

 iu 1840, by Mr. Prosser, of Birmingham. ** He found," to 

 ■quote the words of Mr. Ward, in a paper in Mr. Blashfield's 

 work on mosaic floors, *' that if the material of porcelain (a 

 tare of flint and fine clay) be reduced to a dry powder, and in 

 that state subjected to strong pressure between steel dies the 

 powder is compressed into about a fourth of its bulk, and is con- 

 verted into a "compact substance of extraordinary hardness and 

 density, much less porous and much harder than the common 

 porcelain uncompressed and baked iii the furnace." Messrs, 

 Minton & Co. apply hydraulic pressure to this part of the manu- 

 facture, under which, at every stroke of the press, the powdered 

 clay is converted into a solid tile. 



The design of the pavement in the Conservatory is the work 

 of Mr. Harry Green, formerly a student under the Department 

 of Science and Art, and now attached as artist to Messrs. 

 Minton & Co.'s establishment. It is not of any particular school 

 or period, but is derived from the Pompeian, Early Italian, and 

 Eenaissance art. A large portion of it (the white, green, and 



red tesselation) has considerable resemblance to an elaborate 



