278 Chronicles of Science. [April, 



greater than is found in ordinary gold melting — being 2 • 9 parts in 

 10,000 — ^vliereas in the ordinary process it is 2. The Chairman, 

 in proposing a vote of thanks to the anthor, remarked upon the 

 great importance of the new process. Much of the gold imported 

 into tins country contained 60 or 70 ounces of silver in 1000, 

 which could not at the present time be profitably extracted. The 

 new method would probably be soon adopted by English assayers. 



This was followed by a " Note on the Specific Gravity and 

 Boiling-point of Chromyl Dichloride," by T. E. Thorpe, l)alton 

 Scholar in the Laboratory of Owen's College, Manchester. The 

 author prepared the hquid by distilling an intimate mixture of ten 

 parts sodium chloride and twelve parts potassium dichromate mth 

 thirty parts strong sulj^huric acid. He removed the free chlorine 

 by repeated distillation in an atmosphere of carbonic acid. The 

 specific gravity of the liquid so obtained was, at a tempera tm-e of 

 25° C, 1 • 92. 'i'he boiling-point, at a pressure of 733 millimetres, 

 was found to be 116^ "8. The dichloride cannot, however, be 

 distilled without some slight decomposition. 



The same author, Mr. T. E. Thorpe, then gave a paper " On 

 the Analysis of the Ashes of a Diseased Orange Tree (Citrus 

 aurantium)" The orange plantations along the south-eastern 

 coast of Spain and in the adjacent Balearic Isles have recently 

 been visited with a severe epidemic, the rapid progress of which 

 was naturally viewed with no little anxiety by the people, since 

 the culture and exportation of oranges constitute one of their 

 principal industries. The origin of the disease is involved in com- 

 plete obscurity, and as yet it has bafiled all attempts at remedial 

 measures. The first symptoms are observed in the leaves, which 

 turn yellow and drop off; a most disgusting odour exhales from the 

 roots, and in a few days the tree succumbs. The violence of the 

 disease is now, happily, much abated, and it appears to be dying out. 

 We have no space for the details of the analyses. Tables are 

 given which show the percentage composition of the ash of the 

 roots, stem, branches, and fruit, and the results are compared with 

 the analyses of the ash of healthy plants made by Eowncy and How, 

 and by Dr. Eichardson. The most remarkable differences observed 

 in the comparison are given in the following table, showing the 

 percentages of lime and jihosphoric acid : — 



l.inip. Phosplioiic Acid. 



Root of diseased plant Gl'^2 .. 1'57 



Stcinof ditto 70-67 .. 2-G6 



Eoot of hralthy plant 40-89 .. IB -47 



Stcniofditto 55-13 ,. 17-0'J 



The phosphoric acid is thus shown to be in deficiency in the 

 diseased plant, and the lime in excess. Similar differences cannot, 

 however, be traced in the asli of tlie fruit. 



