252 PHILOSOPHICAL TRANSACTIONS. [aNNO 1675. 



After this some experiinents were made on firmer plants. A green piece of 

 sallow wood was put, part in air and part in vacuo, as above described. On 

 putting into water that part which was in the air, the water presently began to 

 mount, and to pass through the middle of the wood, and incessantly formed 

 bubbles in the receiver, for the space of 24 hours ; which was the water passing 

 through the wood, and in part changed into air. For, making the same ex- 

 periment with a piece of buff, the water mounted also, and passed through it, 

 but it formed no bubbles. Meantime, if there be valves in wood, they must 

 needs be unable to resist the pressure of the air ; for it is noted in sallow, as 

 well as in elm, that the water passes through them with the same ease, what 

 end soever is put in vacuo. 



One day also having put the upper end of a little elm branch in the vacuum, 

 and the lower end in the air, and drenching this latter in water, as had been 

 done the roots of balm in the first of these experiments ; it was a full hour be- 

 fore there appeared any drop of water on the elm leaves in vacuo ; whereas on 

 the balm leaves the drops appeared presently. The cause of which may be the 

 firmness of elm wood. But it may be hard to know why water passing through 

 wood forms bubbles, and in passing through leaves forms nothing but drops. 



Having inverted also this experiment, that is, the leaves in the water with- 

 out the recipient, and the lower end of the branch in vacuo, nothing appeared in 

 two hours time ; having cut a little off the upper end of the branch, which 

 was very tender, a little moisture appeared at the end in vacuo, but enough only 

 to form one drop ; and there appeared no bubble of air. Then cutting the 

 branch a little lower, there was formed one drop of water at the end in vacuo, 

 but it fell not. And having cut the branch yet a little more, the drop of water 

 fell down in vacuo. This shows, that they were not the valves of the plant that 

 hindered the water from passing whilst the branch was entire ; but rather that 

 it was the great tenderness of the leaves, suflfering themselves to l)e compressed 

 by the pressure of the air, so that the water could not insinuate itself between 

 their parts. 



An Account of some Books. N° 120, p. 481. 



I. Francisci Willughbeii de Middleton Armigeri, e Reg. Societate, Ornitholo- 

 gi£E Libri tres ; in quibus Aves omnes hactenus cognitae, in methodum naturis 

 suis convenientem redactae, accurate describuntur ; Descriptiones Iconibus ele- 

 gantissimis et Vivarum Avium simillimis, seri incisis, illustrantur : Totum opus 

 recognovit, digessit, supplevit Joh. Rajus, pariter e Soc. R. Sumptus in Chal- 

 cographos fecit illustriss. D. Emma Willughby, vidua. Lond. 1676, folio.. 



The design of this work is not to give pandects of birds, or to collect indis- 



