5 io 



THE POPULAR SCIENCE MONTHLY. 



the action of water, air, and various gases. 

 While some geologists had supposed that 

 many of these, such as gneiss, greenstone, 

 serpentine, talcose, and chloritic rocks, were 

 igneous products, more or less modified by 

 subsequent chemical action, others main- 

 tained that they were the result of aqueous 

 sedimentation, and subsequently crystallized. 

 This was the teaching of Hutton ; and when 

 early in the present century the crystalline 

 rocks of the Alps were shown to rest on 

 uncrystalline fossiliferous strata, it was 

 suggested that the overlying crystalline 

 strata were newer rocks which had under- 

 gone a metamorphism, to which those just 

 beneath had not been subjected. This view 

 spread until the great crystalline centre of 

 the Alps was considered to be in part of 

 secondary and even of tertiary age. 



The author detailed the course of study 

 by which he was led to question this view, 

 and showed that there is no evidence in the 

 Alps to support it ; that Sedgwick and 

 Nicoll had discredited the palaeozoic age of 

 the crystalline schists regarded by Murchi- 

 son as Cambrian and Silurian ; and, finally, 

 gave the observations by which he had 

 satisfied himself that the crystalline rocks 

 of the Green and White Mountains, and 

 their representatives in Quebec, New Bruns- 

 wick, and on the Blue Ridge, were more 

 ancient than the oldest Cambrian or primor- 

 dial fossiliferous strata. 



Tests for Glycerine. — The so-called pure 

 glycerine of commerce, according to the 

 Journal of Applied Chemistry, is often con- 

 taminated with metallic chlorides. Traces 

 of ammonia are also sometimes present; 

 and it not unfrequently contains oxalic acid 

 or soda. The first-named impurity may be 

 detected by diluting the glycerine with twice 

 its volume of water and adding nitrate of 

 silver. If the glycerine only becomes opa- 

 lescent, the quantity of chlorides is not great 

 enough to be injurious, but, if a flaky pre- 

 cipitate is produced, it indicates that the 

 glycerine is unfit for medicinal use. To de- 

 tect ammonia, mix the glycerine with its own 

 volume of caustic potash, and bring a glass 

 rod previously dipped in dilute muriatic acid 

 over the mixture. If ammonia is present in 

 injurious quantity, whitish vapors of chlor- 

 ide of ammonium will be formed. Oxalic acid 



may be detected, by adding lime-water, ace- 

 tate of lime, or a mixture of chloride of cal- 

 cium and acetate of soda. If the glycerine 

 becomes turbid within five minutes after the 

 reagent is added, it should be rejected. 

 Traces of soda can only be revealed by 

 evaporating the glycerine to dryness, and 

 testing the residue. 



American Origin of the Garden Rasp- 

 berry. — Although the garden raspberry 

 (Eubus Idceus) was imported from Europe, 

 yet Dr. Asa Gray has lately made known 

 some facts that would seem to make it cer- 

 tain that this plant, which is not indigenous 

 to Europe, is a native of Japan and North 

 America. Wild specimens from British 

 America and the Rocky Mountains, it seems, 

 must be referred by the botanist to the culti- 

 vated species, Rubus Idceus. Prof. Ares- 

 choug, who has devoted special study to the 

 Rubi of Europe, concludes that this species 

 did not originally have its home in Europe, 

 but that its origin is to be found in the east 

 of Asia, namely, Japan and the adjacent 

 countries, and perhaps in North America. 

 He also thinks that " the Asiatic and North 

 American floras have reciprocally mixed 

 with each other by passing Behring Straits 

 and the islands which in its neighborhood 

 form a bridge between the two continents." 



Rapidity of Vegetable Growth. — A writer 

 in the Gardener's Chronicle gives some il- 

 lustrations of the prodigious activity mani- 

 fested in the growth of plants during a few 

 weeks. The process of growth, being grad- 

 ual and noiseless, and moreover of every- 

 day occurrence, is generally disregarded. 

 And yet, what a quantity of water must be 

 absorbed and exhaled, how much air inhaled 

 and exhaled, how much carbon fixed during 

 the process ! The writer gives some meas- 

 urements of an ordinary plant, the Abies 

 nordmanniana, a species of silver-fir, which 

 will give a good idea of the rapidity of 

 growth. 



The shrub was only two feet six inches 

 in height, and the number of young shoots 

 of this year's growth on it 585. These 

 shoots vary in length from half an inch to 

 six inches, and their aggregate length is 

 1,1*71 inches, or nearly 98 feet. Dividing 

 the aggregate of the shoots (1,171 inches) 





