Improvements in Science. 293 



1. Chloride of naphthaline* of Laurent is obtained by 

 combining chlorine with naphthaline without heat. It is a 

 white powder, but may be obtained in rhomboidal plates 

 by solution in ether. Smell strong. Melts at 284°. When 

 distilled, it is decomposed, but it may be volatilized in an 

 open tube. Insoluble in water ; little soluble in alcohol; 

 more soluble in ether. Boiling sulphuric and nitric acids 

 decompose it. Potash takes up muriatic acid from it. 

 Potassium destroys it. It consists of carbon 45, hydrogen 

 2-9, chlorine 52-1. 



2. Chloro-naphthalase. — When chlorine begins to act upon 

 naphthaline, an oil is formed which it is difficult to separate 

 from the preceding chloride and naphthaline. By dissolv- 

 ing it in ether, and allowing it to stand for some hours, the 

 latter separates. Lastly, by dissolving it in alcohol and 

 allowing it to settle, we observe that the solid chloride 

 precipitates first, then the oily chloride, and last of all, the 

 naphthaline. In this way it may be isolated. It contains 

 carbon 60 - 9, hydrogen 3'9, chlorine 35*2. 



3. Chloro-naphathalese. — When naphthaline is treated 

 with chlorine ; after being liquified, the matter becomes 

 solid. A product is obtained which affords chloro-naph- 

 thalese by the simple action of potash. The product is 

 placed in a retort along with a strong solution of potash in 

 alcohol. Heat is applied and the alcohol collected. Pour 

 a little water on the residue, the excess of potash and some 

 chloride of potassium will be separated. An oil is deposited 

 which is treated again with alcohol and potash. It is then 

 precipitated by water. In a few hours it becomes a pearly 

 mass crystallizing by sublimation. This is chloro-naph- 

 thalese. It consists of carbon 6L4, hydrogen 3', chlorine 

 35-6. 



4. Perchloro-naphthalese. — If, instead of treating the 

 preceding body with potash, we distil it, it is partly de- 



* Laurent employs a new nomenclature to designate this numerous class of 

 compounds. It consists in changing the vowel of the final syllable of the name 

 of the substance in proportion as the hydrogen is replaced by combining bodies. 

 Chloro-naphthalase will contain 2 atoms of hydrogen less than naphthaline, and 

 will have gained 2 atoms of chlorine. Chloro-naphthalese will contain 4 atoms of 

 hydrogen less than naphthaline, and will have gained 2 atoms of chlorine. Chloro- 

 naphthalise is not known. Chloro-naphthalose contains 8 atoms of hydrogen less 

 than naphthaline. 



