ADDITIONAL NOTES. 499

earth's centre; ſun's heat penetrates but a few feet in ſummer; ſome mines are warm; warm ſprings owing to ſubterraneous fire; ſituations of volcanoes on high moun- tains; original nucleus of the earth; deep vallies of the ocean; diſtant perception of earthquakes; great attrac- tion of mountains; variation of the compaſs; counte- nance the exiſtence of a cavity or fluid lava within the earth. NoTzr VIL--ELEMENTARY HEAT.

CoMBINED and ſenſible heat; chemical combinations attra& heat, ſolutions rejeT heat; ice cools boiling wa- ter ſix times as much as cold water cools it; cold produc« ed by evaporation 3; heat by devaporation; capacities of bodies in reſpe& to heat, 1. Exiſtence of the matter of heat ſhewn from the mechanical condenſation and rare- fation of air, from the ſteam produced in exhauſtinga re- ceiver, ſnow from rarefied air, cold from diſcharging an air-gun, heat from vibration or fridon; 2. Matter of heat analagous to the ele&tric fluid in many circum- ſtances, explains many chemical phenomena.

NoTEr VIIL--MzMyoN's LyYRE.

MecHanIcaL impulſe of light dubious; a glaſs tube laid horizontally before a fire revolves; pulſe-glaſs ſuſ- pended on a centre; black leather contra&ts in the ſun- Mine; Memnon's ſtatue broken by Cambyſes.

NoTE IX.--LuMiNous INSECTS«. ſpecies of glow-worm, their light owing to their reſpiration in tranſparent lungs; Acudia of Surinam