178 



NOTES ON THE BURSTINC4-P0INT 



very simple, consisting of a flask, A, such as chemists use for 

 wash-bottles, having a syphon-tube, E, connected with a square 

 white glass bottle, B, which rested on the stage of the microscope, 

 inclined at an angle of 45^, one of its sides thus serving as a hot 

 stage. Another tube, G, passed through the cork of this bottle 

 and served as a waste-pipe, in order to keep up a constant flow 

 of water from the flask through the bottle. Thermometers, D D, 

 were placed in the flask and in the bottle. Heat was then applied 

 to the flask, and so a constant stream of water, gradually increasing 

 in temperature, was kept flowing through the bottle. 



The starch to be examined was then mixed with a little water, 

 and placed on a thin cover-glass, inverted on the side of the 

 bottle, so that the Starch-cells were in immediate contact with the 

 bottle, and protected by the cover-glass. 



This arrangement was found to work very well. The error due 

 to the difference of temperature between the water in the bottle 

 and the surface of the glass was evidently very slight ; but what- 

 ever it was, the results were all strictly comparable, as the same 

 apparatus was used for all the experiments. 



The accompanying sketch will shew at a glance the arrange- 



19. 



ment of the hot stage. 



Fig. 



A, Flask. B, Glass Bottle, 

 with square sides. C, Cork. 

 D D, Thermometers. G, Glass 

 Syphon-tube. F, India-rubber 

 Connecting-tube. G E, Syphon- 

 tubes from bottle, one to the 

 flask, the other for overflow. 

 H, India-rubber-lengthening to 

 overflow-pipe. I, Spirit-Lamp. 

 K, Tripod-stand. 



