CHEMISTRY. 



100 



on the snow in remote regions of Norway. In 

 n !>,.[ <-ase was it possible that these particles 

 r >u!il liave had u terrestrial origin, and hence 

 Nr>k'ii^ki<>!<l ivirards them as associated with 



oteors. The substance is a silicate having the 

 iiuilu 2RSi + AlSI, + (H). It also contains 

 in tallic particles (iron, nickel, and cobalt), 

 ami ail-Mil two per cent, of organic matter. 



. 1 Improved Cement. A very slow-setting 

 sturro or cement, which becomes extremely 

 LIT 1. is prepared by the addition of a small 

 .tv of alum to plaster of Paris. A still 

 tin.T cement one which sets with equal slow- 

 ness and acquires the same hardness is ob- 

 taitiod by simply plunging the dehydrated 

 jryp-Mirn for a few minutes into water contain- 

 ing slightly more sulphuric acid than suffices 

 to transform into sulphate all the carbonate of 

 calriuin which may be present in the gypsum. 

 After the liquid has been drained off, the plas- 

 ter is submitted to a heat approaching redness 

 for two or three hours. 



Solvent Action of Water on Lead. The dis- 

 cussion in the French Acad6mie des Sciences 

 on the action of water on lead (a summary 

 of which was given in the volume for 1874) 

 was the occasion of Sir Robert Christtson mak- 

 ing a very thorough investigation of the sub- 

 ject. His results agree in the main with those 

 attained by the majority of the French savants. 

 They may be summed up as follows: 1. The 

 purest waters act the most powerfully on lead, 

 corroding it, arfd forming a carbonate of pe- 

 culiar and uniform composition. 2. All salts 

 impede this action, and may prevent it alto- 

 gether, some of them when in extremely mi- 

 nute proportions. 8. The proportion of each 

 salt required to prevent action is nearly in the 

 inverse ratio of the solubility of the compound 

 which its acid forms with the oxide of lead. 

 The first of these three propositions is often 

 called in question, bat all the experiments made 

 by the author invariably confirmed it. A 

 sample of very pure spring-water was sent to 

 him, with the assurance that it had been found 

 incapable of attacking lead ; but on trial it 

 was- found to corrode the lead with as much 

 energy as distilled water. An interesting fact, 

 first observed by Dr. Nevins, is confirmed by 

 the author's researches, viz., that some salts 

 seem to allow of a certain action going on 

 when they are largely present in water, though 

 when they exist in very small quantities they 

 prevent action. 



This curious circumstance might well excite 

 alarm in the minds of those who receive their 

 water-supply through leaden pipes: according 

 to Sir Robert Christison, however, "there is 

 reason to suppose that the proportion required 

 to permit action is greater than is ever likely 

 to occur in waters applicable to household use." 

 Doubtless this excess of salts is found in some 

 mineral waters, and the passage of such waters 

 through leaden pipes may have the effect of 

 corroding the latter. Oftentimes the corrosive 

 action of water has been confounded with the 



corrosive action of other agent* ; fur example, 

 when a load pipe has been stirnnm-l.-.i with 

 mortar, which U frequently or perma- 

 nently moistened, or when lumps of l'r---!i mor- 

 tar have fallen upon the bottom of a lead ci- 

 tern. Again, the effect of galvanic action bat 

 been mistaken for the effect of corr<>-i-,n l.y 

 water. If a lead pipe be soldered with pewter 

 solder and not with lead, erosion takes plaro 

 near the line of junction of the solder with 

 the lead. The name is to be said of the con- 

 tact of the pipe with bars of other metals, or 

 bits of such metals lying on it ; and some facts 

 seem to indicate the existence of the same 

 property in certain stony and earthy substances. 

 Other investigations of this general subject by 

 Fordos, Robierre and Cbamponillon, Maralo, 

 Mayencon and Bergeret, and Dumas Belgrand 

 and LeBlanc, have been published during the 

 year. 



Ozone. The statement of SchOnbein, that 

 ozone is produced by the action of light npon 

 oil of turpentine, is negatived by the later re- 

 searches of Kingsett. He first endeavored to 

 ascertain the rate of absorption of oxygen by a 

 given amount of turpentine and similar bodies, 

 and found that the former, in sunshine, absorbed 

 86.6 cubic centimetres of oxygen daily, but in 

 the shade only 0.6 c.o. Oil of caraway ab- 

 sorbed 8 c.c. daily ; oil of bergamot, 8 c.c. ; oil 

 of juniper, 2.5 c.c. ; oil of cubebs 2 c.c. ; oil of 

 lemon, 1.2 c.c. ; naphtha, 0.7 c.c. ; ether, 0.19 

 c.c; benzole showed no absorption during 

 forty days. On agitation then with potas- 

 sium iodide and starch solution, the well-known 

 blue coloration was more or less quickly de- 

 veloped, though the color did not appear at 

 once, and, in the case of the bergamot, re- 

 quired several minutes. On testing the sub- 

 stance formed for ozone, neither lead nor 

 manganese paper was affected, nor were their 

 solutions changed by actual contact with the 

 oil ; a mixture of sulphuric and chromic acids, 

 however, became violet. Further experiments 

 were made with the oil of turpentine. Thus 

 a quantity of this substance was placed in a 

 bottle with an equal volume of water, air was 

 slowly drawn through it for many hours, and 

 it was allowed to stand several days in a shal- 

 low dish exposed to the air. The water on 

 examination colored starch-paper blue, pre- 

 cipitated manganese dioxide from potassium 

 permanganate and gave a violet color with 

 chromic and sulphuric acids, but caused no 

 change either in lead acetate or manganese 

 sulphate. The oil, even after washing, gave 

 both the starch and the chromic-acid tests. 

 Hence it appears that, even after washing, ox- 

 idized oil of turpentine contains a body with 

 the reactions of hydrogen dioxide. Still it 

 cannot be either ozone or hydrogen dioxide, 

 but a body derived from the turpentine by 

 the action of air and water upon it. If it be 

 the hydrate of terpene oxide, C, H, 6 O.H t O, 

 zinc chloride must destroy it. Active turpen- 

 tine was therefore distilled with zinc chloride, 



