Chemistry and Physics. 521 



ments made with substances of various classes, are given in the 

 form of tables. They show that when an acid and a base neutral- 

 ize each other an increase of electromotive force occurs in almost 

 all cases ; a similar increase taking place in eighty per cent of the 

 cases even when the acid is neutralized by a carbonate. When 

 saline solutions or acid solutions are mixed with each other very 

 little change of electromotive force is noticed ; though consider- 

 able changes are produced when saline solutions are mixed with 

 acids. The above experiments were made with dilute solutions, 

 one gram-equivalent of the substance being dissolved in 100 gram- 

 molecules of water. — Phil. Mag., V, xxxiii, 28, 1892. g. f. b. 



2. On the Preparation of Acetylene. — A convenient method 

 for the preparation of acetylene from inorganic materials has been 

 described by Maquonne. Barium carbide is first prepared by 

 mixing 20 grams of precipitated barium carbonate with 10*5 

 grams of powdered magnesium and 4 grams of retort carbon, 

 previously heated in a platinum crucible ; this mixture being 

 placed in au iron bottle of about 700 c. c. capacity, to the neck of 

 which is attached an iron tube 2 cm. in diameter and 30 cm. long. 

 On heating the bottle to redness, an energetic reaction ensues, 

 sparks being projected from the tube. When this ceases the tube 

 is closed and the bottle is rapidly cooled. The product is a mix- 

 ture of magnesium oxide containing about 38 per cent of bai'ium 

 carbide, with a trace of cyanide and some carbon. It is a light, 

 porous, friable, amorphous mass, gray in color, permanent in dry 

 air and not attacked in the cold by chlorine or hydrogen chloride. 

 Acid oxides or chlorides, even phosphoric chloride clo not act on 

 it at 100° ; but at a red heat it burns in air with vivid incandes- 

 cence ; as it also does in chlorine, vapor of sulphur and hydro- 

 gen chloride. When treated with water, or alcohol, or as a rule 

 with any compound containing hydroxyl, at the ordinary tem- 

 perature, barium carbide yields acetylene. If water be allowed 

 to fall upon the carbide drop by drop, a regular current of 

 acetylene is obtained containing two or three per cent of hydrogen 

 and no appreciable trace of any other hydrocarbon, the yield being 

 about two thirds of that calculated from the mass of magnesium 

 employed. On passing the acetylene through a long glass tube 

 heated to a dull redness, the author has obtained several grams of 

 synthetic benzone in one day. — C. P., cxv, 558; J. Chem. Soc, 

 lxiv, ii, 62, Feb. 1893. G. f. b. 



3. On a New Alcohol of the Fatty Series. — The trunks of the 

 tree Alnus nicana, growing in Finland, were observed to be 

 covered in the summer time, with a white powder. This powder, 

 which was found to be a secretion from certain glands on the 

 back of the plant louse Pyslla alni living upon the tree, has been 

 examined by Sundwik. The dry insect was collected in quantity, 

 exhausted first with hot ether and then repeatedly with hot chloro- 

 form. The latter solution on cooling deposited silky needles 

 having the properties of an alcohol and the composition C 33 H 65 (OH). 

 From its origin the author calls it psyllostearyl alcohol. It fuses 



