486 PHILOSOPHICAL TRANSACTIONS. [aNNO 1754. 



Fig. U, represents the instrument immerged in its cistern of water, ready for use. ab, is the 

 cistern; c, tlie cover; which, when the instrument fig. 10 is raised on blocks, goes on between the 

 bar EF and the basis bc. d, a handle to take otF the cover, when hot; k, the mercurial thermo- 

 meter; F, the cock to let out the water, gh, a hollow piece of tin, which supports seven spirit 

 lamps, which are raised higher or lower by the screws l and k, in order to give the water in the cis- 

 tern a proper degree of heat. 



A Table of the expansion of metals; showing how much a foot in length of 

 each grows longer by an increase of heat corresponding to 180 degrees of Fahren- 

 heit's thermometer, or to the difference between freezing and boiling water, 



expressed in such parts of which the unit is equal to the lOOOOth part of an inch. 



1 White glass barometer tube 100 1 1 Brass wire 232 



2 Martial regulus of antimony 130 12 Speculum metal 232 



3 Blistered steel 138 13 Spelter solder, viz. brass 2 parts, zink 1 247 



4 Hard steel 147 14 Fine pewter 274 



5 Iron 151 15 Grain tin 298 



6 Bismuth l6'7 l6' Soft solder, viz. lead 2, tin 1 301 



7 Copper hammered 204 17 Zink 8 parts, with tin 1, alittle hammered 323 



8 Copper 8 parts, mixed with tin 1 218 18 Lead 344 



9 Cast brass 225 19 Zink or spelter 353 



10 Brass l6 parts, with tin 1 229 20 Zink hammered half an inch per foot . . 373 



It is now several years, says Mr. S. since I first observed the very considerable 

 expansion of the semi-metallic substance called zink, spelter, ortootanag; and 

 proposed it tis more fit for the purpose of making compound pendulums, and 

 metalline thermometers, than brass ; as its expansion seemed considerably greater, 

 and its consistence, when gently hammered, not much inferior. With the same 

 view I have made trial of several other metallic compositions, besides what is 

 above set down; but they all proved much inferior to zink in expansion, and 

 most of them in consistence. 



It seems, that metals observe a quite different proportion of expansion in a 

 fluid, from what they do in a solid state; for regulus of antimony seemed to 

 shrink in fixing, after being melted, considerably more than zink. 



LXXX. On the Sex of Holly. By Mr. John Martyn, F. R. S. Professor of 

 Botany in the Universiti/ of Cambridge, p. 6 13. 



The holly, agrifolium, or aquifolium, is described by all authors as bearing 

 hermaphrodite flowers ; but Mr. M. thinks that this tree is male and female in 

 different plants. He had in his garden at Streatham in Surry, 6 pretty large 

 plants, with differently variegated leaves, in full flower, 3 males, and 3 lemales, 

 growing in pairs, and a male growing by itself, in another part of the garden. 

 The female is that which has been described by authors, and he did not know 

 that any one had described, or even taken the least notice of the nsale. 



