194 LECTURES. 



FIGURE. 



(11.) Bodies being limited portions of matter must possess figure or 

 form. 



Figure and extension are sometimes called the mathematical affec- 

 \tions of matter. 



(12.) Many bodies possess forms peculiar to themselves. 



Forms of animals and plants, are distinctive marks which serve to 

 identify the species. 



All inorganic matter is capable of assuming regular geometrical 

 forms called crystals. See constitution of bodies. 



Amorphous mass. 



Liquids and gases have no peculiar form but assume that of the 

 vessel in which they are contained. 



DIVISIBILITY. 



(13.) Every body is capable of being separated into parts, and these 

 again into other parts and so on, until the portions become so minute 

 as to escape our senses. 



Much discussion relative to the infinite divisibility of matter. The 

 demonstrations given in the older books refer to the infinite divisibility 

 of space, and prove nothing as to the actual divisibility of matter. 



(14.) It is convenient to adopt the hypothesis that matter is divisi- 

 ble only to the degree of what is called the ultimate atoms. These are 

 supposed to be indestructible, and endowed with permanent properties. 



According to this hypothesis a number of atoms form a molecule — a 

 number of molecules a compound molecule, and a number of the latter 

 a particle. 



Atomic Theory of chemical combination. 



Explanation of definite composition of bodies on this theory. 



Atomic volumes of different groups ot different bodies. 



(15.) Actual divisibility of matter carried to a great extent. 



Examples of division of metals, &c. 



Gold and silver leaf. 



Gilding on embroidering thread — a single grain ot gold on thread 

 of this kind has been divided into 3,600,000 parts, perceptible through 

 a microscope magnifying 500 times ; and each part exhibiting the 

 properties of the metal. 



Wollaston's method of making exceedingly fine wire — finest Yol'h-a 

 of an inch in diameter. Hollow glass thread of extreme fineness. 



(16.) Divisibility of matter in solution. 



One grain of blue carmine tinges 10 lbs. of water, which is calcu- 

 lated to give 60 millions of blue particles — the carmine itself is a com- 

 pound substance. 



Metallic solutions and chemical tests. 



(17.) Illustrations from organized bodies. 



The thread by which the spider suspends himself is composed of 

 6,000 single threads. 



Diameter of the globules of the blood, which give the red color, 

 4000th part of an inch. 



