CHEMISTRY. 



closely, and a small indentation near the other 

 end. A glass float is also made and attached 

 to a piece of platinum wire bent at right an- 

 gles. To make an observation, a small quantity 

 of the substance is melted in the indentation 

 of the plate, and while still liquid the platinum 

 wire of the float is placed in it and allowed to 

 become fixed by cooling. The plate is then 

 attached to the thermometer, and the whole is 

 heated in mercury till the float is liberated by 

 the melting of the substance. The thermome- 

 ter tells the temperature. 



Andrews has described a simplified form of 

 the air-thermometer of Crafts for determining 

 temperatures above 350C. The thermometer 

 part consists of a capillary tube bent twice at 

 right angles, on one end of which is a bulb of 

 about one centimetre capacity, and on the other 

 end a wider tube about fifteen centimetres 

 long. At the point where the tube widens is 

 a point of black glass to serve as an index, and 

 in the middle of the wide tube is a glass cock. 

 To the end of this wide tube is attached a rub- 

 ber tube with two branches, one of which goes 

 to a closed manometer and the other to a rub- 

 ber bag. The bag, the manometer, and the 

 wide tube are filled with mercury. To make 

 an observation, the rubber bag is compressed 

 till the mercury rises to the black glass index 

 and the height of the mercury column in the 

 manometer is noted. The thermometer is then 

 exposed to the temperature to be measured, 

 the column is again adjusted, and the new height 

 ^ noted. From these data and the constants of 

 the instrument the temperature may be calcu- 

 lated. 



M. D'Arsonval has invented an apparatus for 

 uninterruptedly preparing oxygen without the 

 agency of heat. It is based upon the mutual 

 decomposition of peroxide of hydrogen and 

 chromic acid. The apparatus is composed of 

 two flasks, one containing clippings of binoxide 

 of barium, the other bichromate of potassium 

 dissolved in hydrochloric acid in excess. The 

 two flasks are connected by an India-rubber 

 tube, which also conveys the stream of chromic 

 solution to the binoxide of barium. The hy- 

 drochloric acid in excess in contact with the 

 binoxide produces peroxide of hydrogen, which, 

 in contact with chromic acid, decomposes and 

 causes the chromic acid to decompose. Thus 

 a stream of oxygen is generated by two dis- 

 tinct decompositions, and is easily regulated 

 by controlling the flow of the liquid. 



Tommasi has described a simple apparatus, 

 which he calls a dissocioscope, for showing the 

 dissociation of ammoniacal salts. It consists 

 of a tube of glass in which is suspended a slip 

 of blue litmus-paper, previously moistened 

 with a solution, completely saturated, and ex- 

 actly neutral, of ammonium chloride. If the 

 tube be plunged into a cylinder containing 

 boiling water, the ammonium salt is dissociated 

 and the^ blue litmus-paper becomes red. On 

 placing it in cold water the dissociated ammo- 

 nia and hydrogen chloride reunite, and the 



paper becomes blue again. This may be re- 

 peated any number of times at pleasure. 



VEGETABLE CHEMISTRY. Dr. E. Ray Lankes- 

 ter controverts the assumption that chloro- 

 phyl, under the influence of sunlight, has the 

 property of decomposing carbonic acid. The 

 action never takes place except when living 

 protoplasm is present in intimate association 

 with the chlorophyl, and Dr. Lankester ad- 

 duces a number of facts to show that it is 

 really due to the protoplasm. Among them 

 is the fact that the rays absorbed by the 

 chlorophyl are not the most efficient ones in 

 promoting the decomposition, while light that 

 has traversed a solution of chlorophyl is still 

 competent to excite the chemical process in 

 question. The action of light, on the other 

 hand, on the chemical motion of protoplasm 

 is known to be very important, in that it pro- 

 motes oxidation and the decomposition and 

 disruption of the protoplasmic parts of the 

 cell; and Pringsheim has suggested that the 

 true function of chlorophyl is by its general 

 absorbent action on light to protect the proto- 

 plasm of the cell from excessive oxidation, and 

 especially the protoplasm of the chlorophyl 

 corpuscles ; while the protoplasm of these cor- 

 puscles, under the influence of the rays of light 

 that pass the chlorophyl, decomposes carbonic 

 acid and synthesizes starch. Dr. Lankester re- 

 gards this explanation as reconciling the diffi- 

 culties in the question. The fact, moreover, 

 that in the organic world generally, the more 

 complex chemical processes connected with 

 nutrition and secretion appear to be carried on 

 directly under the influence of the living sub- 

 stance of the cells, renders it probable on a 

 priori grounds that the living protoplasm is 

 the active agent. 



M. Leon Bontroux, of Caen, has deduced 

 from the examination of the ferments in fruits 

 some facts that are interesting, though hardly 

 conclusive, respecting their origin. Using Pas- 

 teur's method for ascertaining whether a body 

 is charged with ferments, he introduced the 

 body, after employing all necessary precau- 

 tions, into a wine-must deprived of germs, 

 which was then raised to a temperature of 86. 

 The foreign organisms that were developed 

 with the ferments were then eliminated by 

 methodic cultivation. Certain green fruits, in- 

 cluding black currants, gooseberries, raspber- 

 ries, and barberries, seemed to bear peculiar 

 alcoholic ferments normally on their surface. 

 Other fruits like strawberries, cherries, and 

 currants did not exhibit them ; but the most 

 active ferments, those which produce wine, 

 appeared suddenly on the ripe fruits. Seeking 

 to find where the minute fungi that thus ap- 

 pear exist during the growing season, M. Bon- 

 troux discovered that they were borne in great 

 abundance in nectariferous flowers, where the 

 ferment grows at the expense of the saccharose 

 of the nectar. This, then, is w r here the fungus 

 lives during the spring and summer previous 

 to the maturation of the fruit. The transfer- 



