A F F 



[9] 



A G A 



applied to the tongue is nearly 

 insipid, though strongly styptic; 

 it leaves a metallic taste in the 

 mouth. It is poisonous ; sugar 

 acts as a specific against its poison- 

 ous effects. 

 .^EsxrvA'TioBr. (astivatio, Lat.) 



1. The effect produced by summer 

 heat. 



2. The mode in which the parts of 

 a flower, taken separately, are ar- 

 arranged in the bud. 



JE'TITES. (aero?, Gr. aetite, Fr.) 

 Eagle-stone ; a variety of oxide of 

 iron mixed with clay. It is found 

 in masses, generally under, the form 

 of a rounded knob, something re- 

 sembling a kidney. It prevails in 

 the coal formations of England, 

 Wales, and Scotland, has a rough 

 surface, and is of a brown colour. 

 Specific gravity 4 to 7. Lustre of 

 the exterior metallic. It frequently 

 contains a sort of kernel, which 

 rattles on being shaken. It was 

 formerly in repute for several ex- 

 traordinary magical as well as 

 medical properties, such as prevent- 

 ing abortion, discovering thieves, 

 &c. It derives its name from a 

 a popular notion that it was found 

 in eagles' nests, where it was sup- 

 posed to prevent the eggs from 

 becoming rotten. See Nodular Iron 

 Ore. 



AFFI'NITY. (affinis, Lat. affinite, Fr. af- 

 finitd, 1 1) The tendency which bodies, 

 dissimilar in their composition, have 

 to unite and form new compounds. 

 Different bodies are possessed of 

 different attractive powers, and if 

 several be brought together, those 

 which have the strongest mutual 

 affinities enter first into union. 

 Affinity, like sensible attraction, 

 varies with the mass and the dis- 

 tance of the attracting bodies. That 

 the course of affinity increases as 

 the distance diminishes, and the 

 contrary, is obvious ; for it becomes 

 insensible when the distance is 

 sensible, and exceeding great when 



the distance is exceedingly dimin- 

 ished. Affinity agrees with sensible 

 attraction in every point which it 

 has been possible to determine. 



AGALMA'TOLITE (from u^a\/ma and 

 \i'0os, Gr.) Figure-stone. A sub- 

 species of talc- mica, of different 

 colours, as white, red, brown, green, 

 and grey. It occurs massive. It 

 feels greasy, is translucent, and has 

 a conchoidal fracture. The finest 

 specimens are brought from China. 

 It does not contain any magnesia, 

 but in other respects it has the 

 character of talc. 



A'GABIC. (agaricm, Lat.) The generic 

 name for the mushroom, a genus 

 of the order Fungi, class Crypto- 

 gamia. Gmelin enumerates nearly 

 400 species. 



A'GARIC MINERAL. A variety of soft 

 carbonate of lime. It is found in 

 the clefts of rocks, or the bottom of 

 lakes, in pieces loosely cohering, 

 and it is so light as nearly to swim 

 upon water. It obtains its name 

 from its resemblance to a fungus in 

 colour and texture. 



AGAR'ICIA. A genus of lamellated 

 stony polypifers, fixed with flat, 

 subfoliaceous expansions, the upper 

 surfaces only having stelliferous 

 grooves: the stars sessile, lamellous, 

 and in rows. This genus, which 

 much resembles Pavonia, differs in 

 having one surface only of its foli- 

 aceous expansions furnished with 

 stelliferous grooves. 



A'GATE. (achates, Lat. a^ar^s, Gr. 

 agate, Fr. agata, It.) A siliceous, 

 semi-pellucid gem, of which there 

 are many varieties, not of great 

 value. Agates are principally com- 

 posed of quartz with various colour- 

 ing matters. Agates may be arti- 

 ficially coloured by immersion in 

 metallic solutions. Mr. Allan says 

 " Agate is an impure variety of 

 calcedony, of frequent occurrence in 

 the vesicular cavities of atnygdaloi- 

 dal rocks.- It presents the most 

 brilliant and the most varied colours, 



