CHEMICAL SCIENCE. 



DIVISIBILITY OF MATTER. 



MANY years ago, a curious calculation was made by Dr. Thomson, 

 to show to what degree matter could be divided, and still be sensible to 

 the eye. He dissolved a grain of nitrate of lead in 500,000 grains of 

 water, and passed through the solution a current of sulphuretted hydro- 

 gen, when the whole liquid became sensibly discolored. Now a grain of 

 water may be regarded as about equal to a drop of that liquid, and a 

 drop may be easily spread out so as to cover a square inch of surface. 

 But under an ordinary microscope the millionth of a square inch may 

 be distinguished by the eye. The water, therefore, could be divided 

 into 500,000,000,000 parts. But the lead in a grain of nitrate of lead 

 weighs 0.62 grains ; an atom of lead cannot weigh more than 

 1,310, 000, 000,000th of a grain, while the atom of sulphur, which, 

 combined with the lead, rendered it visible (in the mass?), could not 

 weigh more than 1-2,015,000,000 ; that is, the two billionth part of 

 a grain. 



But what is a billion, or, rather, what conception can we form of 

 such a quantity? We may say that a billion is a million of millions, 

 and can easily represent it thus: 1,000,000,000,000. But a school 

 boy's calculation will show how entirely the mind is incapable of con- 

 ceiving such numbers. If a person were able to count at the rate of 

 200 in a minute, and to work Avithout intermission twelve hours in a 

 day, he would take, to count a billion, 6,944,944 days, or 19,025 years 

 319 days. But this may be nothing to the division of matter. There 

 are living creatures so minute, that a hundred millions of them maybe 

 comprehended in the space of a cubic inch. But these creatures, until 

 they are lost to the sense of sight, aided by the most powerful instru- 

 ments, are seen to possess organs fitted for collecting their food, and 

 even capturing their prey. They are, therefore, supplied with organs, 

 and these organs consist of tissues nourished by circulating fluids, 

 which must consist of parts or atoms, if we please so to term them. 

 In reckoning the size of such atoms, we must not speak of billions, but 

 perchance of billions of billions. And what is a billion of billions ? 

 The number is a quadrillion, and can be easily represented thus : 

 1,000,000,000,000,000,000,000,000 ; and the same school boy's calcu- 

 lation may be employed to show that to count a quadrillion, at the rate 



