VOL. LXXIX.J PHILOSOPHICAL TRANSACTIONS. 6l3 



attraction for clay, the basis of the alum, should combine with its acid and form 

 sulphur. If this reasoning be true, then it follows, that the vitriolic acid has a 

 stronger affinity to the inflammable principle than it has to phlogisticated air; 

 and the process with the green vitriol and manganese is to be explained by the 

 operation of a double affinity: the inflammable principle of the volatile alkali 

 joins with the calx of iron, the basis of the vitriol, or with the manganese, and 

 the phlogisticated air with the dephlogisticated air produced by the acid in the red 

 heat. Those who chuse to reject the doctrine of phlogiston must make the ne- 

 cessary alterations in these expressions; but the reasoning will be much the same. 



END OP THE SEVENTY-NINTH VOLUME OP THE ORIGINAL. 



/. Discovery of a Sixth and Seventh Satellite of the Planet Saturn-, with Remarks 

 on the Construction of its Ring, its jitmosphere, its Rotation on an Axis, and 

 its Spheroidical Figure. By JVm. Herschel, LL.D., F, R. S. Anno 17 gO, 

 vol. LXXX, p. 1. 



In a short postscript, added to Dr. H's last paper on Nebulae, he announced 

 the discovery of a 6th satellite of Saturn, and mentioned that he intended soon 

 to communicate the particulars of its orbit and situation to the e.s. He now 

 however presents an account of 1 new satellites instead of one, which he dis- 

 covered by means of his large 40-foot telescope; and has called them the 6th 

 and 7 th, though their situation in the Saturnian system intitles them to the 1st 

 and 2d place. This he did that in future we may not be liable to mistake, in re- 

 ferring to former observations or tables, where the 5 known satellites have been 

 named according to the order they have hitherto been supposed to hold in the 

 range of distance from the planet. 



The planet Saturn is, perhaps, one of the most engaging objects that astrono- 

 my offers to our view. As such it drew Dr. H's attention so early as the year 1 774 ; 

 when, on the l7th of March, with a 54-feet reflector, he saw its ring reduced 

 to a very minute line, as represented in fig. 1, pi. 7. On the 3d of April, in the 

 same year, he found the planet as it were stripped of its noble ornament, and 

 dressed in the plain simplicity of Mars. See fig. 2. Dr. H. passes over the 

 following year, in which, with a 7-feet reflector, he saw the ring gradually open, 

 till it came to the appearance expressed in fig. 3. He observes, that the black 

 disc, or belt, on the ring of Saturn, is not in the middle of its breadth; nor is 

 the ring subdivided by many such lines, as has been represented in divers treatises 

 of astronomy; but that there is one single, dark, considerably broad line, belt, 

 or zone, on the ring, which he always permanently found in the place where the 

 figure represents it. From his observations it appears, that the zone on the 



