122 Proceedings of the 



ing silversmiths have long 1 known. The superiority of lead, as the 

 cold metal, was referred to its great expansive force by heat, com- 

 bined with its deficient conducting power, which is not a fifth of 

 that of copper, silver, or gold ; so that the heat accumulates much 

 more at the point of contact in it, than it could do in the latter 

 metals, and produces an expansion in that^ respect proportionably 

 greater. 



Mr. Trevellyan's paper had been read to the Royal Society of 

 Edinburgh, but is not yet published. Mr. Faraday stated that Mr. 

 Trevellyan had very liberally allowed him the use of a written copy. 



May 6th. Mr. Lindley on the Pitcher Plant. On this evening 

 Mr. Lindley brought before the meeting some illustrations of the 

 plants that have those remarkable appendages which botanists call 

 Pitchers or Ascidia. 



He remarked that appendages in which water or fluid collects 

 have been noticed in a variety of plants ; but that he did not pro- 

 pose, upon the present occasion, to advert to any in which the 

 pitchers do not form a striking and principal feature of the vegeta- 

 tion. These he stated to be the following. 



Firstly, all the species of Sarracenia, little North American 

 swamp-plants, in which the pitchers are hollow, green, sessile 

 bodies, arising from the crown of the plant, and surrounding the 

 scape ; they are furnished with a projecting membranous wing on 

 their face, are terminated with a green leaf-like lid, and are covered 

 inside with numerous inverted hairs. 



The second kind of pitcher plants was said to consist of the 

 various species of Nepenthes, which are found growing in the marshes 

 and ditches of China, and the damper parts of India. In these the 

 pitchers were described as hollow bodies, similar to those of Sar- 

 racenia, and, like them, furnished with a sort of lid, but differing in 

 having a long stalk, which in the lower half is leafy and flat, and in 

 the upper, where it joins the pitcher, cylindrical and twisted ; and 

 also in proceeding from the stem in the place of leaves, instead of 

 forming a cluster of pitchers, arising from the base of the scape at 

 the surface of the ground. 



A third kind, a native of swamps in New Holland, the Cepha- 

 lotus follicularis, was compared to Sarracenia, in regard to the 

 organization and position of its pitchers, but was stated to be 

 remarkable for the presence of flat leaves of an elliptical figure 

 among them. 



All the foregoing were said to be either herbaceous plants, or at 

 least not more than undershrubs; that is in the case of nepenthes, inter- 

 mediate between herbaceous and shrubby. Trees or climbing plants 

 were next mentioned, as sometimes having appendages to which 

 the name of pitchers might be applied, although destitute of the 

 remarkable lid which exists in all the kinds previously named. 



Thus in the Dischidia Rqfflesiana and Clavata, two plants found 

 the one in the Indian Archipelago, and the other on the coast of 



