68 report — 1859. 



On the different Points of Fusion to be observed in the Constituents of Granite. 



By M. F. BlALLOBLOTZKY. 



On the Formation of Rosolate of Lime on Cotton Fabrics in Hot Climates. 

 By F. Crace Calvert, Ph.D., F.R.S., F.C.S. 



The author exhibited some pieces of calico which were covered with red stains, and 

 he stated that a short time previously the cargoes of two ships on arrival in India had 

 been found to be extensively damaged by these stains. After a great number of experi- 

 ments he had found those stains to be due to rosolate of lime, the formation of which he 

 traced to the following cause. Amongst the packing or materials used to surround the 

 bales and protect them from wet and injury, was a kind of waterproof felt made of 

 corded cotton bound together and strengthened by a layer of gutta percha which had 

 been dissolved in impure coal naphtha, the cloth thus made having been then pressed 

 between cylinders. Under the influence of the warm and damp atmosphere of India, 

 the hydrate of oxide of phenyle, or carbolic acid, became volatilized, and coming in 

 contact with the carbonate of lime contained in the calico, was transformed into 

 rosolate of lime. The correctness of this result was proved by enclosing pieces of 

 white calico in bottles with pieces of the felt, the calico being uppermost ; and also by 

 placing a little carbolic acid at the bottom of the bottles instead of the felt, the bottles 

 being kept at a temperature of 110° Fahr. for several days, when in both instances 

 the calico exhibited red stains identical with those which he had previously found in 

 the goods returned from India. 



On Crystallized Bichromate of Stro?itia. By Dr. Dalzell. 



On the Economical Preparation of Pure Chromic Acid. 

 By Dr. Dalzell. 



Dr. Dalzell having experimented on large quantities of material, recommends as 

 the result of his investigation, the process of Traube for the production of the impure 

 acid and its perfect purification by from four to seven recrystallizations, and com- 

 pression of the products between large porous tiles. He describes the modifications 

 in colour and density which chromic acid presents, according to the process by which 

 it has been prepared. 



Before applying the baryta test for its purity, Dr. Dalzell reduces with alcohol and 

 nitric, not hydrochloric acid ; and he states that when the solution of sesquioxide was 

 diluted, twelve hours at least should be allowed for the action of the test before the 

 purity of the product was affirmed. 



Dr. Dalzell also proposes bichromate of strontia as a means of obtaining pure chro- 

 mic acid. He gave the particulars of the process for obtaining the strontia salt of 

 absolute purity from carbonate of strontia and commercial chromic acid. Bichromate 

 of strontia crystallizes with three atoms of water, all of which it loses at 212° Fahr. 

 He has obtained from it pure crystallized neutral and acid chromates of many of the 

 metals by employing equivalents of their soluble sulphates. 



Dr. Dalzell gave the particulars of the composition of several of the metallic chro- 

 mates ; and referring to the action of bichromate of potash on a solution of chloride of 

 barium, stated that when the temperature of the liquid is raised to the boiling-point, 

 Peligot's salt is abundantly formed. He recommends this as the best method for 

 preparing the bichromate of the chloride of potassium. The author stated that he was 

 at present engaged in further researches on the crystallized chromates. 



Dr. Daubeny exhibited specimens of several varieties of Volcanic Tufa from the 

 neighbourhood of Rome and Naples. 



Reports from the Laboratory at Marburg. By Dr. Guthrie. 



