Progress of Invention. 79 



and two valves opening upwards ; the pump to which we direct 

 attention, of only a barrel, a solid plunger, and a single valve. The 

 former pump is exposed to great wear and tear, and very considerable 

 friction, from the necessity for the sucker fitting the barrel exactly ; 

 the latter is totally free from these objections. Our readers may 

 make an excellent model of the new pump by fitting water-tight 

 into one end of a cylindrical glass gas chimney a piece of wood or 

 cork, in the centre of which is an aperture, closed within the glass 

 cylinder by a flap of leather, which will act as a simple, but tole- 

 rably water-tight valve ; and selecting for the plunger a thick rod of 

 wood that nearly fills the cylinder. To work the apparatus, it is 

 only necessary to insert the plunger in the cylinder, fill the space 

 around it with water, and place the closed end of the cylinder in a 

 small quantity of that fluid. When the plunger is drawn up, the 

 valve opens, and water rushes in to supply the vacuum. When the 

 plunger is then pushed in again, the water flows out through the 

 upper end of the cylinder : and thus the process may be continued 

 for any length of time. It is evident that the fluid may be made to 

 issue from a spout or tube, if the upper end of the barrel is enlarged. 

 The principle on which this pump produces its effect is the same as 

 that of the common pump, but it might be supposed that, instead of 

 water rushing up through the valve, water, and even air, would pass 

 down from around the plunger. This, however, is not the case ; 

 and it is the most curious circumstance connected with the appa- 

 ratus. It may be accounted for, however, by the capillary attrac- 

 tion which exists between the plunger and barrel. Experiment alone 

 can show how large such a pump may be made, or from what depth 

 it would cause water to ascend ; but there are most probably many 

 purposes for which it would answer well. 



New Respiratory Diving Apparatus. — Cosmos states that M. 

 Rouguayrol has introduced a reservoir of compressed air, furnished 

 with a mechanism (not explained) for allowing the air to escape in 

 the proportion wanted for submarine respiration. Experiments 

 made in the Napoleon Basin at Eocbefort have been successful. 

 The apparatus is also recommended to enable persons to enter a 

 deleterious atmosphere. 



Crystal Patterns on Glass and Porcelain. — M. Kuhlmann, 

 continuing his communications to the Erench Academy on crystal- 

 lization, gives a process which it would be easy to try on a small 

 scale. If, for example, a solution of sulphate of zinc and a little 

 gum is thickened with chromate of lead, and laid on glass, and the 

 glass heated in a muffle, he obtains a crystalline pattern, shown up 

 in relief by a green tint imparted by the chromic oxyde. Nitrate of 

 potash and nitrate of lead, thickened with gum, and containing 

 powder of coloured enamels, he also finds to afford satisfactory 

 results. 



Miscellaneous. — Among the Tecent improvements in tele- 

 graphy, one of the most interesting, perhaps, is the acoustic tele- 

 graph, in which a note sounded at one place is reproduced at 

 another. It is founded on the fact that a sound is emitted when- 

 ever a sufficiently strong electric current is made to begin or 



