NOTES. 



6 39 



plcxion, and claim descent from white men. 

 Masas is perhaps the same as Mashash, 

 which occurs in the Egyptian documents 

 applied to the Tamahus. The Masas wear 

 the hair in the same fashion as the Tama- 

 hus, and General Faidherbe is inclined to 

 think that they, too, are the descendants of 

 the dolmen-builders. 



Dcep-Sca Photometer. A deep-sea pho- 

 tometer, or instrument for measuring the 

 chemical power of the solar ray at great 

 depths in water, was shown at the late Lon- 

 don Exhibition by Mr. C. W. Siemens. A 

 roll of sensitive paper, hermetically closed 

 in a glass tube, is placed in a thick disk at- 

 tached to the bottom of an iron frame to be 

 dropped by a wire into the sea. In the 

 frame is an electro-magnet. The tube is 

 held in a dark recess till the magnet is 

 formed, and then it springs into the light, 

 but is withdrawn again when the electric 

 current ceases. The actinic force of the 

 rays is, of course, determined from the 

 amount of darkening produced on the paper 

 in a given time. 



Cheap Hydrogen Gas. The statement 

 comes from Paris that a Mr. Giffard has de- 

 vised a process for the rapid production 

 of hydrogen from water, which promises to 

 make its use as an illuminator more eco- 

 nomical than that of ordinary coal-gas. It 

 is claimed that by this method hydrogen 

 may be generated on a large scale, 18,000 

 cubic feet per hour, at a cost of from fifteen 

 to thirty cents per thousand cubic feet, so 

 that by combustion with solid refractory 

 substances, such as magnesium, platinum, 

 lime, marble, etc., it may advantageously 

 compete with coal-gas for illuminating pur- 

 poses. 



Building-Stone and Fire. Dr. Adolph 

 Ott, in the Engineering and Mining Journal, 

 treats of the resistance offered to fire by the 

 various kinds of stone employed in build- 

 ing. According to this author, the presence 

 of magnesia in limestone (magnesian lime- 

 stone, dolomite) hastens the decomposition 

 of the mass under the action of heat, the 

 magnesia parting with its carbonic acid at 

 the comparatively low temperature of 600 

 Fahr. Common limestone will stand a high- 



er temperature without decomposition. As 

 our Westchester and also Vermont marble 

 is a magnesian limestone, this fact is of very 

 considerable interest for this city. It ap- 

 pears that, in Chicago, as also probably in 

 Boston, the sandstones made the most ob- 

 stinate resistance to the heat. This is ex- 

 plained by the fact that the chief ingredient 

 in stones of that class is quartz, a substance 

 remarkable for its infusibility. As for 

 granite, gneiss, mica-slate, and other rocks 

 of the primary formation, which are com- 

 monly esteemed indestructible, Dr. Ott 

 shows that they can make but very feeble 

 resistance to heat. The water enclosed in 

 such rocks accounts for their bursting and 

 exploding when heated. Portland cement- 

 stone is said to show extraordinary resist- 

 ent power, almost equalling sandstone in 

 this respect. Of brick walls the author is 

 disposed to think well, provided they be 

 honestly built of hard material throughout, 

 and of the requisite degree of thickness. 



NOTES. 



Notwithstanding the high price of meat 

 and the great scarcity of potatoes in Eng- 

 land, there are this winter, says the Satur- 

 day Review, 40,000 less paupers in London 

 than three years ago. This is owing to an 

 organized system of transferring labor to 

 portions of the country where it is most 

 needed, and thus relieving the overstocked 

 points where pauperism is always most rap- 

 idly developed. The Review calls for an ex- 

 tension of the system, and urges those who 

 are wasting their funds in ill directed chari- 

 ties, which oftentimes actually increase the 

 number of paupers, to give this one, which 

 aims to make the lower classes self-sustain- 

 ing, a fair amount of consideration. 



Mr. T. C. Webb, of Philadelphia, has 

 made experiments with a plate electrical 

 machine, in an insulated room, that seem to 

 show the fallacy of the ordinary theory of 

 the discharge of a charged conductor. A 

 room eight by nine feet, and about eight 

 feet high, was constructed, and suspended 

 upongutta percha, and its perfect insulation 

 shown by a Thomson galvanometer. The 

 plate-machine acted in all respects the same 

 as in an uninsulated room ; sparks were 

 given off, and the conductor completely dis- 

 charged when touched to the sides of the 

 building. The experiments given in the 

 Philadelphia Magazine seem to show con- 

 clusively that the common theory of the 

 electrical machine is erroneous. American 

 Manufact u rer. 



