870 SEC.' 13. CHEMISTRY. 



2775. Diagram, illustrative of a lead smelting furnace 011 

 Pilz's principle, for the use of lecturers on metallurgy. 



Prof. Dr. Diirre, Aix-la- Chapelle . 



These diagrams are drawn to scale, and can also be employed for teaching 

 constructive drawing and as designs for smelting works. 



2415d. Seven different metal Wires of equal Strength 

 and Weight, for determining the Specific Gravity from 

 their length, by means of a scale. 



The Breslau Committee. 



VIII.-MODELS, DIAGRAMS, APPARATUS, AND CHE- 

 MICALS USED IN TEACHING CHEMISTRY. 



2444. Series of J-inch cardboard cubes, with different colour 

 for each chemical element on which its symbol, atomicity, and com- 

 bining weight are marked, illustrating the laws of chemical 

 combination and the binary theory of Salts. 



Rev. Nicholas Brady , M.A. 



Only a comparatively small number are sent, as they will sufficiently show 



represents the molecule of water, 



their method of use, thus H H 







the dyad oxygeu requiring two monads to satisfy it, the chemical equivalent 

 of the compound being 1 + 1 + 16 = 18. 



2445. Lecture-Boom Diagrams of Alkali Works and 

 Sulphuric Acid Plant. Tn 4 sheets. Prof. Roscoe, F.R.S. 



I. Sulphuric Acid Plant. 



Sheet No. 1. General plan, showing the arrangement of the most modern 

 form of sulphuric acid plant, drawn to scale, with descriptions. 



Sheet No. 2 contains a longitudinal section of the apparatus and chambers 

 on the line C D, sheet No. 1. 



Sheet No. 3 contains a sectional elevation of the same apparatus on the 

 line A B, sheet No. 1. 



Details on sheet No. 2 and sheet No. 3 show various points of importance 

 on an enlarged scale. 



No less than 850,000 tons of sulphuric acid were made last year in Great 

 Britain. The diagrams show the most approved method for the manufac- 

 ture of this important acid, together with the best arrangement of the plant, 

 and are so fully numbered and explained that further description appears 

 unnecessary. 



II. Alkali Works. 



Sheet No. 4 is an enlarged plan of a model alkali works, showing the best 

 arrangement of the various portions of the works ; also fully lettered and 

 Cumbered. As in the above case a description appears unnecessary. 



