428 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



volume of nitrogen Avill weigh 14 ; one of oxygen 16 ; one of 

 fluorine 19 ; one of chlorine 35.5. As these gases unite in equal 

 yolumes or multiples of equal volumes in forming chemical com- 

 pounds, the smallest portion which can enter into combina- 

 tion may be distinguished as an atom, therefore the bars de- 

 signating the density of the gases, may be taken as the relative 

 weight of atoms which are supposed to be of equal size. The 

 conception of an atom must not be limited by size and weight. 

 It is in fact the source of force. Several years ago I advanced the 

 hypothesis that the ultimate atom is a hollow sphere containing 

 and surrounded by the imponderable ethereal element, and inces- 

 santly moving to and from its own center. Whatever may be 

 its condition in chemical combination, it assumes its original form 

 and motion on being released and isolated. 



The arrangement of the elementary gases in figs. 2, 3, and 4, has 

 another important signihcation. Oxygen unites with all other 

 elements except fluorine and is electro-negative. From the posi- 

 tion of oxygen passing around the diagram downward and then 

 upward, we find these gases in the order they are found in electro- 

 lysis. Hydrogen being to the other four, electro-positive. The 

 o-ases and other non-metallic elements are arranged so that ele- 

 ments belonging to the same family are found in close proximity, 

 and thus their atom-holding power or atomicity in chemical com- 

 bination may be clearly understood. 



Hydrogen, fluorine, chlorine, bromine, and iodine have the low- 

 est atom-holding power; they are monatomic, or monads. Oxy: 

 o-en, sulphur, selenium, (also tellurium,) are diatomic, or dyads. 

 Nitrogen, phosphorus, boron, (also arsenic,) are triatomic, or 

 triads. Carbon and silicon are tetratomic, or tetrads. 



The chemical combination of tAvo gaseous elements and their 

 resulting volume, are illustrated by a series of diagrams. It is sup- 

 posed that not less than two volumes of each element enter in 

 combination, but the process is rendered more intelligible by 

 representing the union of single volumes. 



Figure 6 shows a volume of hydrogen and one of chlorine, 

 which, under the influence of light, combine without condensation, 

 formino- two volumes of hydrochloric acid gas. Although the 

 resulting product of the union of these gases is not diminished in 

 bulk, yet at the instant each electro-positive atom seeks an electro- 

 negative one there is an expansion; this process of mating pro- 

 duces explosion. 



Fio". 7 represents two volumes of hydrogen and one of oxygen 



