10 



KNOWLEDGE 



[January 2, 1893. 



Not only is electricity being now largely used in the 

 production of aluminium from clay, but in other directions 

 also electricity is being made extremely serviceable. For 

 exampb, the manufacture of caustic soda, which was 

 hitherto a slow process, is being carried on fi'om brine by 

 the aid of electricity, chlorine and other chemical products 

 being obtained at the same time. As compared with 

 present methods, the new process is at least fifty per cent, 

 cheaper, and much simpler. The chlorine, which is very 

 valuable, is saved for the production of bleaching powder. 

 It seems probable that the chemical industries of the 

 country will be greatly modified and benefited by the elec- 

 trical methods now being introduced. 



At the recent anniversary meeting of the Eoyal Society, 

 the president (Lord Kelvin) referred in his address to an 

 extra number of the " Proceedings " (No. 310) which is 

 devoted to a first report of the Water Itesearch Committee 

 on the present state of our kmw ledge concerning the 

 bacteriology of water, by Professors Percy Frankland and 

 Marshall Ward. This committee was appointed by the 

 society, in alliance with the London County Council. The 

 report is full of most valuable information regarding the 

 vitality of micro-organisms in drinking water, to which in 

 a large measure the spread of Asiatic cholera, typhoid 

 fever, and other zymotic diseases is now known to be due. 



Mr. W. H. Preece, the well-known electrician, has 

 succeeded in sending a telephonic message from the shore 

 of the Bristol Channel, near Cardiff, to the island of Flat- 

 holm, three miles off, without the intervention of a con- 

 necting wire. This truly wonderful result seems to open 

 out a great vista of future possibilities. 



A HIGHLY interesting discovery of human remains has 

 lately been reported from the Riviera. The caves in which 

 the bones were found were discovered in 1872 by a W. Riviere, 

 and since that date explorations have been vigorously carried 

 on. The skeletons that have been discovered belonged to 

 a long-headed (dolichocephalic) race, and the individuals 

 they represent were e%idt ntly strong and muscular. Three 

 more skeletons were discovered early last year, one of 

 which represented a tall man, whose height was about 

 6 feet C inches ; with these bones were found necklaces 

 made of fish bones, canine teeth of stags, shells, &c. 

 Some of the stone implements found with the bones were 

 finely worked, but none of them polished, and some of the 

 bone implements were very rudely made. Many mamma- 

 lion bones were also found, but none of extinct species, or 

 even ot reindeer. But the absence of polished stone imple- 

 ments seems to indicate an early period in the stone age — 

 say the beginning of neolithic times. There is still one 

 cave unexplored, and the Prince of Monaco, whose property 

 it is, has given orders that the work of excavating it is to 

 begin next spring. One curious fact about the human 

 bones here discovered is, that those belonging to adults 

 are all f jund to have been painted red with peroxide of 

 manganese ; and the Marquis de Nadaillay, who reports 

 the discovery in Science (September 23rd), says that a 



similar custom was observed by some Indian tribes. 

 — I • I — 



The remains of ancient lake-dwellings, well known in 

 Scotland and Ireland under the name of " crannogs," are 

 very scarce in England. But Dr. R. Mnnro, in the Times of 

 October '24th, calls attention to a newly-discovered example 

 in Somersetshire. The discovery was made by Mr. Arthur 

 Bulleid, of Glastonbury, whose observations are of special 

 interest. The site of this ancient lake-village is about a 

 mile north of Glastonbury, on the road to the village of 



Godney. A number of low mounds were noticed here, 

 each rising from one to two feet above the surrounding 

 soil, and extending 20 to 30 feet across. Excivations 

 having been made, some of the original piles were dis- 

 covered. The total number of mounds is between sixty 

 and seventy, and they extend over an area of some five 

 acres. Each mound, it seems, contains a fireplace. The 

 hearths were generally formed of large stone slabs, placed 

 over a bed of clay, or of small stones embelded in it in 

 the form of a pavement. An old seventeenth-century map 

 of the district shows that it contained a lake called " The 

 Meare Poole," into which three streams found their way. 

 This pool was not far dist.mt from the site of the present 

 discovery. It is probable that the lake once covered a 

 larger area. Bronze rings, fibulie, a broach, and a few 

 decayed iron objects have been found here ; pottery is 

 abundant ; also articles of bone and horn, and some flakes 

 and cores of flint. Articles of "late Celtic" date pre- 

 dominate, and at present nothing Roman has turned up. 

 It is to be hoped that this interesting site will in time be 



thoi-oughly excavated. 



— •-♦-• — 



There has lately been some discussion in one of our 

 evening papers on a question of considerable importance 

 to " the masses," viz., whether tinned meats, shell-fish, 

 fruits, &c., are sometimes poisonous, and what are the 

 causes that produce the jroison. One cause is supposed to 

 be the lead used in some inferior kinds of solder. The 

 lead is believed in this case to be dissolved by meat acids, 

 or the acids of fruit, as the case may be. Another supposed 

 cause is the presence of bacteria in- meat, shell-fish, &c., 

 owing to insufficient boiling before the tin is soldered up. 

 Another and more obvious cause is the occasional cracking 

 or breaking of a tin, so that air gets in, and that of course 

 would start decomposition. It is comforting, however, to 

 find that one writer denies the possibility of lead poisoning, 

 and maintains that every precaution is taken by the leading 

 American firms to secure complete sterilization by means 

 of the hot bath. In cases where air has afterwards got in 

 through a crack, the smell ought to bo a sufficient indica- 

 tion of the fact. The deaths from eating tinned foods 

 appear to be a very small percentage when the millions 

 who use tinned eatables are taken into account. 



WHAT IS A NEBULA? 



By A. C. Eanyard. 



IN the article under the above heading published in 

 the October number, it was shown that nebula? are 

 as a general rule extremely transparent, and that 

 the density of the larger nebulfc must be very small, 

 the density of the Orion nebula being probably less 

 than one ten thousand millionth of the density of our air 

 at the sea level. The Orion nebula shines with a faint 

 green light, giving a gaseous spectrum, and if it were a 

 quiescent mass of gas we should expect the cooler outer 

 layers to absorb the radiations given out by the glowing 

 gas within, and its greenish light would consequently not 

 reach us. 



Again, the great transparency of the Orion and many 

 other nebula; would lead us to conclude that even its 

 interior parts can radiate freely into space, and that cou- 

 seijuently they would probably cool rapidly ; but if the 

 nebulous matter is cold, how can we account for its faint 

 luminosity '? 



If we suppose a mass of hot gas consisting of a great 

 variety of chemical elements to be projected into space, 

 most of its chemical constituents would, as the gas cooled, 

 be precipitated into a glowing mist, the particles of which 



