TEANSACTIONS OF SECTION U. 629 



occurs when such a solution is evaporated, the four following cases may be distin' 

 guished : 



(1) Solutions of a single salt. 



(2) Solutions with two or more salts, all of which contain the same acid 

 or basic radical, and form neither double sails nor isomorphous mixtures, 



(3) Two salts that are in a condition to f'orui a double salt. 



(4) So-called ' reciprocal ' salts, i.e., salts which can be formed from two acid'J 

 and two bases. 



Cases 1 and 2 present nothing calling for special notice. In the case of 3, it 

 is shown under what conditions a pure double salt crystallises out of the solution. 

 Similarly, in the case of 4, instances are discussed in which either two or three salts 

 result by evaporation, and an account of new experiments with NII^Cl + NaNO^ 

 in this relation is given. Lastly, the study of the occurrences which are discussecP 

 in the paper is recommended in respect to many technical processes, and ther 

 formation of natural salts. 



5. On some Derivatives of Camphene. By J. E. Marsh and J. A. Gardner. 



6. On Fluorene Diacetate. 

 By Professor W. R. Hodgkinson and A. H. Coote. 



In some previous communications to the Chemical Society by one of us, halogen 

 and other derivatives of fluorene have been described. With the exception of* 

 diphenylenketone, there is no derivative in which it is for certain knovsTi that the 

 methylenic hydrogen is replaced. "When solutions of fluorene, dibenzyl or ace- 

 naphtene are acted upon by chlorine, bromine, &c., substitution invariably takes 

 place in the benzenoid nucleus. 



From the results of some experiments made by one of us on the sulphonates of 

 fluorene and acenaphtene dissolved in strong H.^SO^, it appeared probable that dry 

 chlorine might act upon these hj'drocarbons in the absence of a solvent, and perhaps 

 at some high temperature in a similar manner to its action on toluene, &c. 



Experiment proved this to be the case. 



The hydrocarbons were dried and treated with very dry chlorine at the ordinary 

 room temperature, and also at or about the boiling-point of the respective hydro- 

 carbons. Action commenced immediately, and a tendency was noticed for the 

 chloride produced to distil over in the current of chlorine. 



The action is, however, not quite confined to the methylenic hydrogen, for the 

 chlorides first produced act as solvents for the still uuacted-upon fluorene or 

 acenaphtene, and some substitution in the benzene nucleus takes place. The 

 amount of this can he reduced by letting the chlorine act rapidly. 



By careful distillation under reduced pressure it is possible to effect a partial 

 separation. A better jilan is to dissolve in absolute alcohol, and fractionally 

 crystallise by cooling with a C0„ alcohol bath. 



From fluorene the following bodies appear to be produced : — 



I. If. III. IV. 



CCJ^ C'HCl CCI, CC1„ 



/\ /\ /\ /\" 



H,C,-C,H, H,C,-C,H, H3C„C1-C,H,C1 H,C-0,H,C1 



Acenaphtene is converted almost entirely into a dichloride. None of the 

 chlorinated fluorene products gives diphenylenketone when oxidised under the 

 same conditions as produce diphenylenketone from fluorene. 



One fraction of the chlorinated fluorene which distilled under about 300 mm. at 

 320° to 330° C. gave 29°-52 per cent. CI ; the calculated amount for G^^llfil is 

 30-23 per cent. 



A diacetate was prepared from this by digesting with alcoholic potavssium 

 acetate. On analysis this gave 71'23 per cent, carbon and 3'92 hydrogen — C,3Hg. 

 (CH3COo).3 requires 72-3 C and 4-9 H. This product boiled at 326° to 330° O. at 

 760 mm. pressure. 



