248 PHILOSOPHICAL TRANSACTIONS. [aNNO 1728. 



At 18'' 55"" 48' the eclipse had sensibly been begun. 



IQ 40 47 5 digits were eclipsed. 



20 36 6 the end of the eclipse, very exact. 



At the time ot" this eclipse, many maculas appeared on the sun's disk. 



The same Solar Eclipse, observed at Padua. By Sig. Poleni. N'^403, p. 479. 

 From the Latin. 



Clouds prevented seeing the beginning. 



At 19'' S"" 45^ true time, eclipsed O dig. lO'. 



19 41 27 there were eclipsed 4 dig. 30'. 



20 38 42 the end of the eclipse. 



Some further Observations towards composing a Natural History of Mines and 

 Metals. By Dr. Nicholls, Pnel. Jnat. Oxon, and R.S. S. N°403, p. 480. 



Of Iron. — Of all the substances concurring to form the terrestrial globe, iron 

 probably bears the greatest share; as it not only abounds in most kinds of stone, 

 showing itself in varieties of crocus, all which gain a more intense colour by 

 fire ; but also enters greatly into the composition of common clay ; as may be 

 judged from the similitude of colour between clay and dry iron ore; from the 

 easy vitrification of clay ; from the resemblance between clay so vitrified and 

 the clinkers of iron ; from its deep red colour after calcination ; and lastly, from 

 its yielding pure iron, by being burned wiih oil. 



But while iron is thus entangled with other bodies, it rarely employs the care 

 of the miner ; who finds the expence of reducing it to metal too seldom ba- 

 lanced by the price it yields: for which reason, though we frequently meet with 

 large and rich loads of iron, yet (the woods having been applied to more ad- 

 vantageous uses) they are there entirely neglected. 



When most pure, the ore is found under 3 different appearances. ]. A rich 

 dry ore, whose scrapings exactly resemble an alkohol martis: this kind of iron 

 ore has very nearly the colour of common clay. 2. A rich iron ore, with part 

 of the wall of the load formed by a concretion of yellow crystals. In this 

 stone the iron radiates from points forming segments of spheres, and where 



posing which work it is said his two sisters were greatly assisting to him. The first volume is an 

 excellent introduction to astronomy; and the other three contain numerous calculations. 



3. De Transitu Mercurii per Solem, anno 1723 ; in -Ito, 172-t. 



4'. De Annuls Inerrantium Stellarum Aberrationibus : in 4to, 1729- — Besides tliese he has a num- 

 ber of papers in the Memoirs of the Academy of Sciences ; in several volumes of the Philosophical 

 Transactions, and elsewhere. 



