Lesson XIII. j 



CHEMISTRY. 



1.7 



agitation employed, so as to dissolve the 

 bromine ; afterwards, caustic potash is 

 added, and evaporation and other processes 

 conducted. 



its properties! 

 . y soluble in water, more 

 so in alcohol, and freely in ether. [Ex- 

 j Repeat Experiment 32, 

 using bromine instead of iodine, and the 

 colour is changed to orange-yellow instead 

 of blue. 



. T. ^'hat is FLUOR i 

 P. It is an element that has never been 

 isolated, because as soon as it is separated 

 from one compound, it unites with soir.e 

 other substance. 



T. How do we know that it does 



Because it is found in the fluoride of 

 calahm (fluor, or Derbyshire spar), fluoride 



of silver, &c. It is said to dissolve nearly 

 everything it touches. 



GENERAL QUESTIONS ON LESSi 



1. Name the discoverer of each of the 

 halogens. 



J. What is there peculiar about chlo- 

 rine ? 



3. How is it obtained ? 



4. Illustrate the properties of chlorine 



'rimi'iits. 



:>. What is iodine ? How is it prepared .' 

 anil what are its proper 



6. Illustrate the properties of iodine by 

 experiments. 



7. How is bromine obtained, and what 

 are its properties ? 



8. How is fluorine obtained, and what 

 is there peculiar about it ? 



LESSON XIII. 



you have learned all about the elements of Chemistry, you should then study 

 it more fully ; because it is a science that requires a life-time devoted to it, and even 

 .nnot be mastered, as fresh discoveries are made every day. It is on this account 

 that I have not described the compounds of elements, such as oxides, hydrate?, nitrates 

 chlorides, iodides, bromides, fluorides, &c. When you are better acquainted with the 

 elements, you will learn that these substances form many compounds. For example 

 bromine vapour and hydrogen combine in equal volumes to form lydrobroviic a< 

 oxygen and carbon combine to form carbonic oxide. 



QUESTIONS. 



. i Carbon? 



.ry body, found in many 



,t forms, constituting a large pro- 

 portion of all organic structures, animal 



Actable, and found in a state of 

 purity and crystallised, as graphite or 

 plumbago, and as diamond. Thus, char- 

 coal, black-lead, bone-black, lamp 

 and the diamond are, chemically speaking, 

 the same substance. 



1 (7. y. If the diamond, charcoal, and 

 the other substances you have na 



posed of the same substance, how 

 iliflcr in appearance ? 

 arrange)!. 

 , as I explained to you 



148. T. Is graphite or plumbago pure 

 carbon ? 



/*. Some specimens contain iron ; but 

 the finest specimens of Borrowdale plum- 

 bago consist of pure carbon. 



/'.Is carbon combustible ? 

 /'.Yes, we cm ond as 



well as a piece of charcoal, or any other 

 kind of carl 



What are its properti 

 /'. It is a good conductor of elc<- 

 and a bad conductor of heat. It is not 



itures, but rr.-uli <>xygen 



gas or common air when heated to redness, 

 and leaves only a small quantity of ashes, 

 but generate* a gas called carbonic acid. 



