lxxxviii GENERAL SUMMARY OF SCIENTIFIC AND 



Stenhouse and Groves have shown that, by^the prolonged 

 action of chlorine upon pyrogallol, two new bodies are form- 

 ed, which they call respectively mairogallol and leucogallol. 

 The former is produced by a long-continued action of the 

 gas, and crystallizes from boiling glacial acetic acid, or from 

 mixed ether and glacial acid, in brilliant orthorhombic prisms. 

 Leucogallol forms crystalline crusts composed of minute col- 

 orless needles. 



Lorin has described a method of preparing concentrated 

 formic acid, which consists in adding to concentrated glyc- 

 erin, contained in a tubulated retort, and heated to 87, de- 

 hydrated oxalic acid in powder, repeating the process when- 

 ever the evolution of gas ceases. The formic acid which 

 distills over is rectified, and then contains ninety-four per 

 cent, of real acid. 



Bremer, by the action of phosphorus and iodine upon or- 

 dinary tartaric acid (dextrorotatory) in presence of water in 

 a sealed tube, has succeeded in obtaining from it a new malic 

 acid, which also rotates to the right. He is now experiment- 

 ing upon loevorotatory tartaric acid, in the hope of producing 

 a left-handed malic acid, and by the union of the two an in- 

 active acid. 



Carey Lea has published a valuable modification of the 

 usual iron test for hydrocyanic acid. If a little uranic ace- 

 tate be added to a solution of a ferrous salt, there is thrown 

 down in presence of a soluble cyanide a purple precipitate. 

 One five-thousandth of a grain of hydrocyanic acid gives, 

 when thus treated, a perfectly distinct reaction. He also 

 recommends the use of ammonio-ferric citrate, in connection 

 with ferrous salts, in the Prussian-blue test. In this way 

 one two -thousandth of a grain of potassic cyanide may be 

 detected, a delicacy far greater than has been before claimed 

 for this test. 



The crude acids of the native petroleum of Wallachia have 

 been examined by Hell and Medinger. The second run of 

 the still yields to caustic soda an acid which, after solution 

 in water and treatment with sulphuric acid, collects as an oil 

 on the surface, and is called "mineral oil" by the workmen. 

 This is a mixture of several acids, probably homologous, but 

 their separation is exceedingly difficult. An ethyl-ether of 

 one was finally obtained, whose saponification yielded the 



