CHEMISTRY. 203 



must have originated bej'ond the limits of the light cometary mat- 

 ter of our solar system. Chemical News. 



Daubree has found peridot in all the meteorites examined by 

 him, and this crystal occurs in some of the lowest rocks. Assum- 

 ing meteorites to be planetary specimens, peridot seems to be 

 ubiquitous, and to be, as Daubree calls it, the universal scoria. 

 Oxygen, essential to organic nature, has played an important 

 part in the formation of meteorites, and by inference of planetary 

 bodies generally. 



VOLCANIC FLAMES. 



Dr. Percy, in a lecture on Chemical Geology, observes, " There 

 is still a question whether flame is ever really seen in volcanic 

 eruptions. I know that, in newspaper reports of eruptions, flame 

 is stated to be seen ; but there may not be flame notwithstanding. 

 What is supposed to be so may be merely the vapor of water illu- 

 minated by incandescent matter below, and it is not very easy to 

 distinguish between the two. Still, if hydrogen be evolved, 

 which there is no ground for disputing, there is no reason, con- 

 sidering the high temperature, why flame should not be pro- 

 duced." 



SPECIFIC HEAT OF SOILS. 



According to Pfaundler, " Pogg. Ann., cxxix., 1866," the spe- 

 cific heat of soils ranges from 0.1923 to 0.5069 ; the most common 

 value is 0.25 to 0.30. Soils free from humus have the lowest spe- 

 cific heat, whether they consist of sand or lime ; the richer the 

 soil in humus, the higher is its specific heat ; loamy soils have a 

 high specific heat. So great a variation in this important physi- 

 cal property will explain why a plant sensitive to changes of tem- 

 perature may be unable to grow on soils of low specific heat, 

 however excellent it may be in other respects. 



COBALT AND NICKEL IN IRON. 



The results of the chemical examination of irons are of great 

 importance to the mechanic and engineer. The chemist Weiske 

 has recently examined irons more especially for cobalt and nickel. 

 These are present in English irons in very small quantity, accord- 

 ing to previous observers ; but Weiske states that he finds both 

 cobalt and nickel present in all irons, but in very varied propor- 

 tions. He found the smallest amount in English pianoforte wire, 

 but in some Saxony iron he found as much as 7 grammes of the 

 two metals in a hundred weight of the iron. As these two metals 

 are known to give hardness to iron, their presence, even in small 

 amount, may confer some valuable properties. 



EFFECT OF EXPOSURE ON COAL. 



Prof. Rockwell, in the "American Journal of Mining," has 

 called attention to the deterioration which coal suffers from ex- 

 posure to the weather, and to the importance of keeping it as dry 



