528 



SCIENTIFIC NEWS. 



[Nov. 23, 1 838. 



water-filled cavern, the roof of which is about 500ft. 

 thick. He also thinks it probable that at a given depth 

 and temperature carbonic acid gas may be found in a 

 liquid state. Should the existence of a subterranean sea 

 be established, it would dispose of many theories and 

 scientific speculations as to the source and course of the 

 mineral springs at Saratoga. 



The Equatorial Boundary of the Occurrence of 

 Snow. — H. Fischer {Berlin Gcsellschaft fi'ir Erdkunde) 

 distinguishes between the mean altitude at which snow 

 occurs every winter and the extreme boundary which it 

 reaches in exceptional seasons. The immediate coasts 

 of the Mediterranean, save to the north of the Adriatic 

 and the jEgean, experience a fall of snow only excep- 

 tionally. From the Cilician Taurus the mean limit of 

 snow extends over Mosul to Bagdat and Schiras, rises 

 then to Teheran, and runs over Herat, Candahar, and 

 Kelat in Beloochistan, on the mountains west of the Indus, 

 to 28 N.L. On the southern slope of the Himalayas the 

 boundary runs at about 5,500 feet above the sea level. 

 In the interior of China the limit is not certainly deter- 

 mined. It cuts the Chinese coast to the north of Shanghai, 

 touches the southern parts of Kiuschin and Schik.oku 

 (Japan), and meets the west coast of America in 47j° 

 N.L. Passing through the Rocky Mountains and the 

 Sierra Nevada, it turns downwards, almost to the tropic 

 of Cancer. In Texas it bends to the north again, cross- 

 ing the Mississippi in 315 N.L., leaves America a little 

 to the south of Cape Hatteras, and meets the French 

 coast to the south of Bordeaux. In the southern hemis- 

 phere it follows in general the parallel of 40 S.L. Neither 

 the coast regions of Tasmania nor the western and 

 northern parts of the southern island of New Zealand 

 suffer from snow every year. Along the Andes the line 

 rises to 8° S.L. Snowfalls occasionally in Mesopotamia, 

 Lahore, Canton, in Mexico, but never at the southern 

 point of California. In the southern hemisphere snow 

 occasionally falls along the Blue Mountains of Australia 

 to 27° S.L. In New Zealand only the extreme northern 

 point enjoys an immunity from snow. Snow has been 

 known to fall in Rio de Janeiro, and even in 20 S.L.,a 

 little farther inland. 



The Annual Ring in Trees. — In the course of his 

 last report, the chief of the forestry section of the 

 Agricultural Department of the United States, referring 

 to the annual rings in trees, asserts that these exist as 

 such in all timber grown in the temperate zone. Their 

 structure is so different in different groups of timber 

 that from their appearance alone the quality of the timber 

 may be judged to some extent For this purpose the 

 absolute width of the rings, the regularity in width from 

 year to year, and the proportion of spring wood to 

 autumn wood must be taken into account. Spring wood 

 is characterised by less substantial elements, the vessels 

 of thin-walled cells being in greater abundance, while 

 autumn wood is formed of cells with thicker walls which 

 appear darker in colour. In conifers and deciduous 

 trees the annual rings are very distinct, while in trees 

 like the birch, linden, and maple the distinction is not so 

 marked, because the vessels are more evenly distributed. 

 Sometimes the gradual change in appearance of the 

 annual ring from spring to autumn wood, which is due 

 to the difference in its component elements, is interrupted 

 in such a manner that a more or less pronounced layer 

 jf autumn wood can apparently be recognised, which 



again gradually changes to spring or summer wood, and 

 then finishes with the regular autumn wood. This 

 irregularity may occur even more than once in the same 

 ring, and this has led to the notion that the annual rings 

 are not a true indication of age ; but the double or 

 counterfeit rings can be distinguished by a practised eye 

 with the aid of a magnifying glass. These irregularities 

 are due to some interruptions of the functions of the tree 

 caused by defoliation, extreme climatic condition, or 

 sudden changes of temperature. The breadth of the ring 

 depends on the length of the period of vegetation ; also 

 when the soil is deep and rich, and light has much 

 influence on the tree, the rings will be broader. The 

 amount of light and the consequent development of foliage 

 is perhaps the most powerful factor in wood formations, 

 and it is upon the proper use of this that the forester 

 depends for his means of regulating the development and 

 quantity of his crop. 



The Public Health. — According to the Registrar- 

 General's return for the week ending Saturday, Novem- 

 ber 10th, the deaths registered in 28 great towns of 

 England and Wales corresponded to an annual rate of 

 19/0 per 1,000 of their aggregate population, which is 

 estimated at 9,398,273 persons in the middle of this 

 year. The six healthiest towns were Bradford, Brighton, 

 Hull, Leicester, Halifax, and Wolverhampton. The high- 

 est annual death-rates, measured by last week's mortality, 

 were — for measles, i"8 in Blackburn, 2 - 2 in Portsmouth, 

 3'o in Leeds, and 3'S in Cardiff; from scarlet fever, i'o 

 in Manchester, V2 in Salford, and 2 - 2 in Blackburn ; 

 from whooping-cough, i'o in Birkenhead ; from " fever," 

 i'i in Oldham, 1*3 in Newcastle-upon-Tyne, and i - 6 in 

 Salford; and from diarrhoea, 1/4 in Bolton and in Cardiff, 

 and 1 '6 in Derby. The 45 deaths from diphtheria in 

 the 28 towns included 34 in London, 2 in Liverpool, 

 and 6 in Salford. Small-pox caused 1 death in Preston, 

 and 1 in Hull, but not one in London or in any of the 

 25 other great towns. In London 2,770 births and 

 1,520 deaths were registered. Allowing for increase 

 of population, the births were7o and thedeaths i67below 

 the average numbers in the corresponding weeks of 

 the last ten years. The annual death-rate per 1,000 

 from all causes, which had been 21-2 and 19/7 in the 

 two preceding weeks, further declined last week to i8'5. 

 During the first six weeks of the current quarter the 

 death-rate averaged 19/1, and was 0'4 below the mean 

 rate in the corresponding periods of the ten years 

 1878-87. The 1,520 deaths included 109 from measles, 

 18 from scarlet fever, 34 from diphtheria, 15 from 

 whooping-cough, 14 from enteric fever, 18 from diarrhoea 

 and dysentery, and not one from typhus, ill-defined forms 

 of fever or cholera ; thus 208 deaths were referred to 

 ithese diseases, being 11 below the corrected average 

 weekly number. Different forms of violence caused 50 

 deaths ; 37 were the result of negligence or accident, 

 among which were 17 from fractures and contusions, 

 6 from burns and scalds, and 10 of infants under one 

 year of age from suffocation. In Greater London 3,571 

 births and 1,896 deaths were registered, corresponding 

 to annual rates of 337 and 17-9 per 1,000 of the esti- 

 mated population. In the outer ring 9 deaths from 

 measles, 7 from " fever," 6 from scarlet fever, 6 from 

 diphtheria, and 6 from whooping-cough were regis- 

 tered. Three fatal cases of fever occurred in Croydon, 

 and 3 in Tottenham sub-district, and 3 of measles in 

 Tottenham sub-district. 



