200 
POPULAR SCIENCE REVIEW. 
Professor Hofmann's Banquet. — Professor Rammelsberg having "been 
elected President of the German Chemical Society for the present year, the 
Society gave a banquet to the late President, Dr. A. W. Hofmann. The 
banquet was presided over by Herr Magnus. Among those present were 
the following : Dr. R. Virchow, Prof. Dove, Prof. Pose, Dr. du Bois 
Peymond, His Excellency the Pight Hon. Mr. Bancroft, the United States 
Minister at Berlin, and a very large number of savants from Berlin and other 
parts of Germany. Many of the foreign members sent telegrams of felicita- 
tion, and among these the following was received from M. J. Dumas, Paris : 
“ Your festive meeting is heartily shared by all chemists of the world who 
admire and cherish you.” Just before the meeting broke up, there was dis- 
tributed a photo-lithograph, representing Dr. Hofmann under the emblem of 
Jupiter Ammon (typifying his researches on ammonium), with an aureola of 
aniline colours. A large number of toasts were heartily responded to ; and 
an -ode to aniline, composed for the occasion, caused general applause and 
great merriment. 
Strontia and Ammonia in the Manufacture of Soda. — It is stated by M. 
Ungerer, in the Bern hebdomadaire de Chimie (January 6th), that when to 
a concentrated solution of sulphate of ammonia is added an equivalent quan- 
tity of chloride of sodium, and the fluid heated to boiling-point, mutual 
decomposition of these salts takes place, and sulphate of soda and chloride 
of ammonium are formed ; the former salt separates as a crystalline powder, 
and maybe removed by filtration from the solution of the chloride of ammo- 
nium. The sulphate of soda, having been dissolved in water, may be 
decomposed by caustic strontia, thus yielding caustic soda ; the chloride of 
ammonium may be converted into carbonate of ammonia by means of chalk. 
It is doubtful whether this process, theoretically correct, will be com- 
mercially available. 
GEOLOGY AND PALAEONTOLOGY. 
The Chemical and Mineral characters of Lavas. — In a long and able paper 
on Lavas in the March number of the Geological Magazine , Mr. G. Poulett 
Scrope, in treating of the varying mineral and chemical characters of lavas, 
says that he cannot but think that far too much importance has been attached 
to these distinctions, especially by the German geologists. By many of 
these, as in the instance of Baron von Pichtofen, whose classification of Vol- 
canic Pocks was late reviewed by him ( Geol . Mag., vol. vi. p. 518), these 
differences, in their minutest peculiarities, have been laid down as determin- 
ing the relative age of the respective rocks. There can be no greater source 
of error. It is certain that many varieties of trachyte and basalt, and rocks 
of intermediate mineral character — that is to say, with a greater or less 
proportion of acid or basic elements in their composition — are often found 
succeeding each other as products of the same volcano, in no definite series; 
sometimes one cla«s, sometimes another, having been first ejected. Nay, 
they are to be seen occasionally, though rarely, to pas9 into each other in 
the same mass, just as some granites are found locally passing into syenite, 
an 1 this again into greenstone. There are even lavas, as for example that 
