550 SEC. 13. CHEMISTRY. 



the water used be allowed to flow freely into a vessel, the level of the water 

 must be deducted from the height of the water column above the appara- 

 tus. The vacuometer is made small in order to render the apparatus more 

 handy. The apparatus may also be used without the vacuometer. 



The advantages of the whole apparatus are as follows : (1.) It is very 

 handy ; (2.) It may be used on every work-bench which is provided with a 

 of water ; and lastly (3.) It is very cheap 



2560. Apparatus for producing a Blast of Air by the fall of 

 water. (Catalonian "Trompa".) Dr. Otto Bach, Leipzig. 



2561. Small Copper Steam Generator. 



Julius Schober, Berlin. 



2562. Hofmann's Vapour Density Apparatus. 



Julius Schober, Berlin. 



2563. Hofmann's Filtering Stand, the metal rings of which 

 are lined with wooden rings slanting at an angle of 6O. 



Julius Schober, Berlin. 



2564. Knap's Improved Azotometer. 



Franz Hugcrshoff, Leipzig. 



2565. Wolfs improved set of Sieves with Brushes. 



Franz Hugershoff, Leipzig. 



2566. Winkler's Apparatus for gas analysis. 



Franz Hugershojff, Leipzig. 



One is intended for very small quantities of gases, carbonic acid, &c. Its 

 advantage consists in the considerably narrowed part of the measuring tube 

 above the lower three-way stop-cock, whereby finer divisions are rendered 

 possible. 



The other is constructed with a second three-way stop-cock, in the upper 

 part of the measuring tube, which allows for the easy connexion with any 

 other apparatus. 



2566a. Drawing of Price's Patent Retort Furnace. 



W. Price. 

 DESCRIPTION OF DRAWING. 



Eig. 1. Is a longitudinal section through centre of furnace. 



Fig. 2. A plan through the "retort," "combustion," and "heating" 

 chambers. 



Fig. 3. A cross section through combustion chamber. 



Fig. 4. An elevation, part in section, of the retort chamber. 



Fig. 5. A sectional plan through retort chamber at E E. 



Fig. 1. A is a combustion chamber filled with grate bars in the ordinary 

 way. B, a heating chamber, separated from A by the usual bridge. C, is the 

 neck descending into an underground flue D, leading into an upcast or retort 

 chamber, as it has been designated, E. In the centre of the chamber (E) is 

 a firebrick circular pillar F, with spaces around marked in Fig. 5, E E E E, 

 and on which is placed a cast-iron cylindrical air-vessel G, which is protected 

 by fire-brick. 



