78 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



a relatively simple excitation of six or seven letters suddenly 

 placed before and withdrawn from the eyes, and its reception 

 or formation in the consciousness. In other experiments he 

 found that the time required for the comprehension of a com- 

 plex figure was much greater than that for a single figure ; 

 the proportion between an ellipse and a pentagon, for in- 

 stance, being as 1:5. Researches on the time requisite for 

 the production of consciousness, with various strengths of il- 

 lumination, gave the result that this time was proportionate, 

 within rather wide limits, to the degree of illumination ; but 

 if the illumination was excessively strong or weak, it in- 

 creases. 13 A, November 1, 1871, 500. 



ACTION OF GAS JET ON WATER. 



It is said that if a thin thread of water is passed through 

 the jet from a blow-pipe, it is but slightly warmed, the in- 

 crease in temperature being but three degrees, although its 

 heat is sufficient to melt almost any metal. When passed 

 through an ordinary flame, the increase in temperature is 

 considerably greater, possibly owing to the incandescent par- 

 ticles being carried away by the liquid in smoke. If the blow- 

 pipe jet is directed against a sheet of water, it is not pierced, 

 nor does it produce any sensible heating effect. It is sug- 

 gested that if, instead of the metallic curtains used in thea- 

 tres, a sheet of running water were interposed, it would be a 

 great improvement as a fire guard. 18 A, March 8, 1872, 631. 



ICE EXPERIMENT. 



A simple method of producing ice instantaneously consists 

 in placing a little water in a small watch-glass or porcelain 

 capsule laid upon wool or cotton. The water is then to be 

 covered with a layer of sulphide of carbon, and a current of 

 air directed upon it through a slender tube. The absorption 

 of the heat of the water, in consequence of the rapid passage 

 of the sulphide of carbon to a gaseous condition, is so great 

 that a few seconds are sufficient to solidify the water. A 

 lens of hemispherical and transparent ice is thus obtained, 

 which can be preserved long enough to pass it from hand to 

 hand. 3 i?, May 9, 1872, 90. y 



