4 CHEMISTRY INDISPENSABLE 



at another stronger, are perpetually heard, of their 

 utility to husbandry. To arrive at a right decision 

 upon any subject, it must first be accurately under- 

 stood ; for otherwise the essential preliminary to a 

 correct judgment is altogether wanting. Many of 

 those who entertain such doubts have still, perhaps, 

 no clear idea of the proper nature, design, and powers 

 of chemistry, and for this reason it will best com- 

 port with the end we have in view, to premise a few 

 observations upon the character and objects of this 

 science, as also upon the ways and means by which 

 it seeks to attain its end. 



Every body knows that a piece of iron, when 

 hammered at a red heat, is converted •into black 

 scales, and also, that by exposure to the damp at- 

 mosphere, or burial in moist earth, it changes into 

 rust ; that the expressed juice of the grape is gradu- 

 ally transformed to wine, and this, again, to vinegar; 

 that ^vood in an oven, or oil in a lamp, disappears 

 by combustion ; and that animal and vegetable sub- 

 stances in time become putrid, disorganized, and 

 finally, in like manner, disappear. 



Iron scales and rust are altered iron: iron itself 

 is hard, malleable, of a grayish-white color, and glis- 

 tening; when heated to redness it becomes, with an 

 increase of its specific gravity, black, dull, and brit- 

 tle; when kept in a moist atmosphere, it is con- 

 verted into a brownish-yellow powder. Wine is al- 

 tered juice, called must, in which the sweet taste of 

 the grape-juice can no longer be perceived ; as wine 



