416 SEC. 12. APPLIED MECHANICS. 



2144b. Worm- Wheel, with inclined teeth. 



Royal Geological Institute and Mining Academy (Directoi*, 

 Prof. Hauchccornc)) Berlin. 



2 144c. Annular Wheel and Pinion. 



Royal Geological Institute and Mining Academy (Director , 

 Prof. Hauchccornc), Berlin. 



2144(1. Hypocycloidal Gearing. 



Royal Geological Institute and Mining Academy (Director , 

 Prof. Hauchecornc), Berlin. 



214:4:6. Worm- Wheel, with straight teeth. 



Royal Geological Institute and Mining Academy (Director, 

 Prof. Hauchccornc\ Berlin. 



2144f. Pair of Worm Wheels, with axes at right angles. 

 Royal Geological Institute and Mining Academy (Director, 

 Prof. Hauchecorne), Berlin. 



2144g. Skew Mitres. 



The Committee, Royal Museum, Peel Park, Salford. 

 A pair of toothed mitre wheels mounted on shafts that cross each other. 

 The invention of the late E. Roberts, C.E., of Manchester, 1836. 



2144h. Intermittent Wheels. 



The Committee, Royal Museum, Peel Park, Salford. 

 The larger wheel performs six revolutions for one of the lesser. The 

 invention of the late R. Roberts, C.E., of Manchester. 



2145. Model of Cugnot's Steam Carriage, 1783. 



Conservatoire des Arts et Metiers, Paris. 



2146. Model of a centrifugal smoke purifier. 



Dr. Otto Braun, Berlin. 



This model shows the action of centrifugal force on bodies suspended in 

 gases, by means of it sparks, soot, tar, ammonia, &c. can be removed from 

 smoke. 



2 146 a. TyndalPs Smoke Filter Respirator, suitable for 

 firemen, fire-escape men, and for persons entering deleterious 

 atmospheres. James Sinclair. 



The nitration is by means of dry cotton wool, dipped in glycerine and 

 charcoal. 



2146b. TyndalPs Smoke Filter Respirator, combined 

 with elastic tube, suitable for mining operations, chemical works, 

 breweries, &c. James Sinclair. 



This respirator is designed to enable the wearer to enter and breathe freely 

 in mephitic gases by means of the tube, which can be used in lengths up to 

 90 feet, the wearer being enabled to communicate verbally with those out- 

 side and they with him. 



