VOL. XXTV.] VHILOSOPHICAL TRANSACTIONS. IQ/ 



the opinion of the gentlemen then present, that it did not appear quite so 

 brisk, or so vivid, as at first. 



Exper. 11. — To 2 or 3 small pieces of phosphorus, in a glass dish, was added 

 a small portion of oil of vitriol, tartar per deliquium, and oil of cloves, which 

 mixture fired the phosphorus in the open air: but adding a little common water, 

 the flame was extinguished. This preparation being included in a receiver, 

 very little light appeared : but on exhausting the air, it became very apparent, 

 and sent forth vivid steams. At the same time the ingredients in the dish very 

 much resembled a boiling flame, exhibiting a strong light; so that several objects 

 near it were thence distinguishable; and so continued till the air was admitted, 

 at which time it became opaque. Nor would shaking the engine (by which 

 means the mixture in the dish was put in motion) produce any sensible recovery 

 of light. 



Exper. III. — A small quantity of the said ingredients being put into a bottle 

 with a narrow neck, and included under a receiver, appeared then with very 

 little light; but on withdrawing the air, the phosphorus began to be luminous, 

 and continued to increase, in proportion to the rarefaction of the air, issuing 

 out of the bottle in a pyramidical form. At last, although the receiver was 

 well exhausted, the vivid steams that were then emitted, were so fine and 

 subtle, as to ascend in so thin a medium, reaching the upper parts of the 

 receiver (which was not tall), and descending again by its sides. On letting in 

 the air, the light quite vanished; audit would have been in vain, as 1 have 

 often tried, to have waited in expectation of its recovery in the open air. 



Observations on the Seed-Vessels and Seeds of Poly podium. By Mr. Anthony 

 Fan Leuivenhoeck, F.R.S. N° 297, p. 1868. 



Being at a place where polypodium or fern grew, I viewed the seed vessels, 

 which were in great numbers on its leaves; and when I placed some pieces of 

 a leaf before the microscope, I observed the seed vessels appearing like so many 

 round globules ; and that they burst one after another before my eyes. And 

 lately, in the middle of the last winter, there fell into my hands two leaves of 

 fern, that grew upon the stump of an old willow tree, and were almost 

 withered; which kind we call oak fern. This leaf had a great deal of seed on 

 it, which was much larger than the seeds of the fern that grows in the country. 

 Of these seed vessels, sometimes 13 of them lie in a row by one another. 



Fig. 27, pi. 7» represents the largest part of an oak fern plant; which I call 

 a leaf, because it has no root, but only a stalk ; and as part of the leaf was 

 divided into 17 branches, of which abg is one, we may conclude that the 

 whole leaf consisted of a great many more. I have often counted in one 

 branch only of such a piece of a leaf, and in one row only of such a branch as 



