530 PHJLOSOFHICAL TRANSACTIONS. [aNNO 1 7O9. 



produced, being reflected by the hard, polished, and nearly contiguous body of 

 sulphur, seems to be the reason why it appeared with so much vigour. This 

 outward light would sometimes break into branches all over the lined part of the 

 globe, in as odd, and as pleasant a manner, as what has been noticed in former 

 experiments, with the large globe glass, upon letting in a little air. And when 

 the attrition was ceased, but the globe continuing its motion, abundance of 

 sparks of light would appear all round it, and continue so to do for some time, 

 without any fresh attrition. 



Microscopical Observations on the Particles of Crystalized Sugar, &c. and the 



Manner qf Observing the Circulation of the Blood in Eels. By M. Leuwen- 



hoecky F.R.S. N^ 323, p. 444. 



I have said, in a former Transaction, that the particles of sugar-candy con- 

 sisted of two broad and two narrow sides; and that the other, i. e. the top and 

 bottom, ran into a sharp point, like the figure of a wedge or chissel. The 

 following are some figures of them. Fig. 4, pi. 12, represents a small bit of 

 sugar-candy, of which one can seldom see so perfect a figure ; because they are 

 almost always fastened to some other particles of sugar, so that we can only 

 discover the superficies of one side, as here in this figure hiefg ; but when it 

 is taken out of the syrup or liquor, without being united to any other particles, 

 the other side represented by abcdk will also appear after the same manner. 

 We also observe, that all the particles of the sugar-candy, even that which 

 comes out of the East Indies, if it be not too irregularly coagulated, and 

 fastened to the sides of other particles, has generally one side obtuse, and 

 different from the other three, which have acute angles, just like a square piece 

 of wood, one of the corners of which is partly cut away, as apears at ik. 



Fig. 5 also represents a small particle of sugar-candy, which had been joined 

 to others at the side lmn ; and at o there appears a very small particle of the 

 candy, that seems to have been coagulated with the said figure when it was 

 much smaller ; which particle appeared like mountain crystal, and under it was 

 another, composed of about 10 small crystals. 



For my further satisfaction concerning sugar-candy, and its coagulation in 

 syrup, I took some powdered sugar, arid dissolved it in water, and then boiled 

 it until I supposed all the water was evaporated ; after which I placed it on 

 several glasses, to observe the coagulation of its small particles. Some days 

 after I observed a great many complete figures, which lay coagulated in several 

 shapes, but all of them as clear and transparent as crystal, forming a pleasant 

 sight *. but I expected to have found them all of one and the same shape, and 

 that they would have appeared like figure 4 ; but when viewed with a micro- 



