Chemistry and Physic*. 151 



masses, as in the case of tellurium, titanium and platinum. 

 Moreover the periodic law has detected periodicity in the physi- 

 cal properties of bodies; so that density, elasticity, tenacity, 

 fusing point, heat of formation, magnetic properties and the like 



are now deducible from it. As to chemical properties, the peri- 

 odic law shows not only that the increase of the power of com- 

 bining with oxygen in the elements is accompanied by a corres- 

 ponding decrease in their power of combining with hydrogen, 

 but also that there is a limit to oxidation just as there is to hy- 

 drogenatiou ; so that just as CIT 4 and Sill 4 represent the highest 

 hydrides so RuO H and Os0 4 represent the highest oxides. More- 

 over this law lias demonstrated that the maximum extent to which 

 different non-metals enter into combination with oxygen is deter- 

 mined by the extent to which they combine with hydrogen, the 

 sum of the number of equivalents of both being always equal to 

 eight. Thus CI forms C1H and C1 2 7 ; and since O is bivalent 

 each chlorine atom has seven equivalents in the oxide and one in 

 the hydride, making 8. So sulphur which fixes two equivalents 

 of hydrogen cannot combine with more than six equivalents or 

 two atoms, of oxygen. As to the peroxides, they have a charac- 

 ter special to themselves. The peroxide form of sulphur (the 

 so-called persulplmric acid) stands in the same relation to sul- 

 phuric acid that hydrogen peroxide stands in to water : 



H(OH) or HoO is to (OH) (OH) or H 2 2 as H(HS0 4 ) or H 2 S0 4 is to 

 (HS0 4 ) (HS0 4 ) or H 2 S 2 8 . 



So that the periodic law is strengthened rather than weakened by 

 the existence of peroxides. In proof that the law extends to 

 compounds, a double list of oxides is given with their densities and 

 specific volumes, ranging from Na 2 and K 2 to S 2 6 and Cr 2 6 . 

 In a fourth column the differences are given between the volume 

 of the oxygen compound and that of the parent element, divided 

 by the number of oxygen atoms in the compound; and these dif- 

 ferences steadily increase with the increase of oxygen. — J. Chem. 

 Soc, lv, 634, October, 1889. G. f. b. 



2. On Sonorous Sand in the Peninsula of Sinai / by H. 

 Carrisgton Boltox. — The author describes the results of his 

 personal observations on the sonorous sands of Jebel Nagous, 

 Arabia Petra?a. The paper is in continuation of tw r o others on 

 Musical Sand presented jointly with Dr. A. A. Julien at the meet- 

 ings of the American Association in Minneapolis and Philadelphia. 



The isolated mountain of Jebel Xagousis situated about four and 

 one-half hours northwest of Tor on the Gulf of Suez. On the 

 steep slopes of this mountain rest several large banks of sand ; 

 one of these, called the Seetzen's Bell Slope, after its discoverer, 

 emits distinct musical sounds whenever the sand slides down the 

 incline either spontaneously or through the agency of man. The 

 mountain consists of massive white sandstone carrying quartz 

 pebbles and veins; it is about three miles long and 1,200 feet 

 high. The Bell Slope measures 260 feet across the base, five or 



Am. Jour. Scl— Third Series, Vol. XXXIX, No. 230.— Feb., 1890. 

 11 



