64 PROCEEDINGS OF THE AMERICAN ACADEMY 



peated Laurent's experiments on a larger scale, and showed that his 

 anthracene had the formula Ci^Hjg, melted at 213°, and was the same 

 as Fritzsche's unnamed hydrocarbon. 



In 1867, Fritzsche* described the preparation of his reagent 

 (dinitroaiithrachinone), and its use in the detection and purification 

 of hydrocarbons; and Berthelotf reviewed all the previous work upon 

 anthracene, determining its boiling-point 360° for the first time. 



The next important paper on the subject appeared in 1869, when 

 Fritzsche,! on account of its behavior with his reagent, pronounced 

 anthracene a mixture of two very similar hydrocarbons, which he 

 called photene, melting-point 210°- 212°, and phosene, melting-point 

 193°. 



In the following year (1870) general attention was attracted to 

 anthracene by tlie appearance of Graebe and Liebermann's famous 

 paper § on anthracene and alizarine, in which they not only proved 

 that alizarine was dioxyanthrachinone by j^reparing it synthetically 

 from anthracene, but described a large number of derivatives of 

 anthracene, giving for the first time the melting-point of anthrachi- 

 none 273°. They showed, too, that Fritzsche's photene was identical 

 with anthracene, but were unable to obtain his phosene, which Bar- 

 bier II four years later showed was jirobably a mixture of anthracene 

 and phenanthrene. 



Syntheses of Anthracene. 



In describing the syntheses of anthracene, all those made by the 

 same method will be grouped together, and these groups will be taken 

 up in the order of their discovery. 



1. Limpricht^ was the first (in 1866) who made anthracene syn- 

 thetically, unless, indeed, one of the products obtained by Miircker,** 

 in 1865, from the action of heat on tolallylsulphide must be consid- 

 ered anthracenesulphide, but there seems to be no sufficient ground 

 for this supposition. Limpricht's method consisted in heating benzjd- 

 chloride with water in a sealed tube to 190° for eight hours; the pro- 

 ducts were benzylether, an oil C,^II,^, and anthracene. 



* Zcit. fiir Cliemic, 1867, p. 289. t Bull. Cliem. Soc, viii. 231. 



$ Zcit. fiir Clicmie, 18G9, p. ?.87. 



§ Ann. Ciieni. Pliarm., Supp,, vii. 257. A preliminary notice appeared in 

 18G8, Ber. d. ch. G., p. 49. 



II Comptes Rendus, Ixxix. 121. ** Ibid., cxxxvi. 94. 



TT Ann. Clicm. Pharni., cxx.xix. 308. 



