OP ARTS AND SCIENCES. 821 



met with the fatal accident which so sadly ended his promising 

 career. 



The observations which already had been made interested us so 

 much that in 1886 we undertook a more thorough study of the sub- 

 ject. We had already collected a great deal of material which we did 

 not think it necessary to publish in a preliminary form, when Denaro * 

 published in the Gazzetta Chimica a brief notice of a dichlorpyromucic 

 acid melting at 167-168°, which was evidently identical with that pre- 

 pared by Garratt. The paper contained a description of the acid and 

 two of its salts, but the analyses of the latter did not agree with those 

 which we had already obtained, and moreover contained such serious 

 misprints or arithmetical errors, or both, as to be wholly without 

 value. In consequence of the appearance of that paper, we thought 

 it best to publish a preliminary account f of our work, so far as that 

 one acid was concerned, more especially since our study of it was then 

 essentially completed. 



In repeating the experiments of Garratt, we had no difficulty iD 

 isolating the dichlorpyromucic acid which he had prepared, but we 

 found that the reaction was still more complex than we had supposed. 

 At ordinary temperatures chlorine was rapidly absorbed, but the pyro- 

 mucic acid was soon so coated with the viscous addition product that a 

 homogeneous product could not be obtained. On heating, the reaction 

 could easily be pushed to the end, and the gain in weight closely cor- 

 responded with the addition of four atoms of chlorine. At the same 

 time hydrochloric acid and carbonic dioxide were given off, and the 

 resulting product contained a percentage of chlorine much larger than 

 that demanded by any simple addition product. Under these circum- 

 stances it seemed advisable to return to the ethyl pyromucic tetrachlo- 

 ride of Malaguti, which, from his description and analyses, appeared to 

 be homogeneous ; and to take up the study of the more complex ac- 

 tion of chlorine upon the acid itself after this investigation had made 

 us better acquainted with some of the products likely to be formed. 

 Although we were unable to prepare a perfectly homogeneous product 

 by following the directions of Malaguti, we found no difficulty in so 

 modifying the conditions that the resulting compound should give us 

 pure fiy dichlorpyromucic acid melting at 168-169°, S chlorpyro- 

 mucic acid melting at 176-177°, or trichlorpyromucic acid melting at 

 172-173°. The (38 dichlorpyromucic acid we were unable to prepare 

 by direct substitution, or by saponification of ethyl pyromucic tetra- 



* Gazz. Chim., xvi. 333. t Berichte d. deutsch. chem. Gesellsch., xx. 252. 

 vol. xxiv. (n. s. xvi.) 21 



