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SCIENTIFIC NEWS. 



[Oct. 12, 1888. 



cided to hold the Institute's first examination for local 

 Surveyors and Inspectors of Nuisances on November 

 8th and 9th. A programme of lectures for the winter 

 session is in course of preparation. A letter was read 

 from the Charity Commissioners saying that they con- 

 sidered that the new Institute was likely to prove a 

 powerful means for the diffusion of sanitary knowledge, 

 and promising to grant facilities to the Institute to 

 deliver lectures in the various buildings which the Com- 

 missioners proposed to establish in different parts of 

 London. 



Mexican Agriculture. — In a recent report on the 

 agriculture of the Mexican State of Vera Cruz, the 

 British Consul describes the primitive manner in which 

 maize is cultivated in the Minatitlan district, where three 

 crops are raised annually, but never on the same land. 

 No ploughing is done ; one man makes with a pointed 

 stick a series of lines of holes about two feet apart ; 

 another man follows, dropping two or three grains into 

 each hole, and the rain is left to fill the holes in. The 

 harvest is calculated at a hundred times the weight of the 

 seed, and is gathered in 16 weeks after the planting. No 

 manuring is done, except when the land is first cleared, 

 and then the ashes of the burnt underwood, rank grass, 

 and stumps are used as fertilisers. This method of cul- 

 tivation prevails in remote and low-lying districts ; on 

 the higher levels maize is cultivated on ploughed lands, 

 and farming there is becoming more and more systematic 

 and on many haciendas scientific. Lack of capital is the 

 cause of the exceedingly rude cultivation of cotton, maize, 

 and other products in Mexico. Even in the case of 

 tobacco many planters never plough or manure, and 

 never plant the same land twice, yet the reputation of 

 Mexican tobacco is rapidly increasing, and the manufac- 

 turers of Vera Cruz are increasing the size of their 

 factories and the number of their operatives. The pre- 

 sent annual production is almost 6,000,000 lb., produced 

 at an average cost of 5! per lb. Twenty-three per cent, 

 of the whole is exported, about half of which is manu- 

 factured and goes chiefly to England. 



Old Roman Plank-Roads. — The Prussian Minister of 

 Education, Von Gossler, having learnt that Professor F. 

 Knoke had lately found traces of old Roman plank-roads 

 on the moor between Mehrholz and Bragel, not far from 

 Diepholz, in Lower Hanover, invited that gentleman to 

 fully investigate the matter. He has just completed the 

 task. He was able to trace the lines of two parallel 

 plank-roads right across the moor, presenting all those 

 distinctive features which are found in Roman works of 

 this kind. One of them shows evident signs of having 

 been demolished by force, the boards, which were 

 originally fastened with pegs to the bearers, having been 

 violently torn away and buried in the bog to the right 

 and left of the track. The other road seems to have 

 fallen into decay, but their are signs of repairs executed 

 even during the Roman period. For in places boards 

 have been found fastened over the original planks, the 

 fashion of both being the same. Those repairs seem to 

 have been carried out hastily, for in one place a mallet, 

 employed probably to drive home the pegs, was found 

 on the track, forgotten, no doubt, by the workmen. The 

 local archaeologists feel assured that they have here the 

 pontes longi which were used a.d. 15 by the Roman 

 commander, A. Cascina, in his retreat from Germany to 

 the Ems. 



The Atmospheres of the Stars. — Mr. Orray T. Sher- 

 man {Popular Science Monthly), whilst studying the star- 

 spectra, comprising bright lines, finds that whilst the 

 bright line does not vary in place it may vary in inten- 

 sity. This peculiarity affords a distinction between 

 bright-line light, bright-background space, and any inci- 

 dental disturbance the spectrum-light may suffer. Col- 

 lating his own observations, especially of ji Lyrae, with 

 Lockyer's results on the solar atmosphere, he concludes 

 that we may represent to ourselves the condition of the 

 stellar atmosphere and the action therein somewhat as 

 follows :— An outer layer of hydrogen positively electri- 

 fied, an inner layer of oxygen negatively electrified, and 

 between them a layer of carbon mingling on its edge 

 with hydrogen. The electric spark passing through the 

 mixture forms the hydro-carbon compound, whose mole- 

 cular weight carries it into the oxygen region, when com- 

 bustion ensues with the formation of carbonic acid and 

 watery vapour, both of which, descending under the 

 influence of their molecular weight, are again dissociated 

 by heat, and return to their original positions. Under 

 the insight which this result gives, we have found the 

 spectra of the nebulae referable to low excitation hydro- 

 gen, the spectra of the bright-line stars referable to high 

 excitation oxygen and hydrogen, or hydrogen of lower 

 excitation according as the central star is of high or 

 low magnitude. There is also reason for thinking that 

 a similar atmosphere in similar physical conditions lies 

 between us and the sun, and it seems as if we might 

 consider that from the faintest nebula to the most highly- 

 finished star we have but progressive stages of the 

 phenomenon here presented. 



The Public Health. — The Registrar-General's return 

 for the week ending September 29th shows that the 

 deaths registered during that period in 28 great towns of 

 England and Wales corresponded to an annual rate of 

 1 8 -3 per i,oco of their aggregate population, which is 

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

 year. The six healthiest places were Huddersfield, 

 Halifax, Birmingham, Bristol, Nottingham, and Oldham. 

 In London 2,395 births and 1,314 deaths were regis- 

 tered. Allowance made for increase of population, the 

 births were 325 and the deaths 94 below the average 

 numbers in the corresponding weeks of the last ten year?. 

 The annual death-rate per 1,000 from all causes, which 

 had been i6"2 and i5 - 8 in the two preceding weeks, rose 

 again last week to i6'0. During the 13 weeks ending 

 on Saturday last the death-rate averaged i6 - 2 per 1,000, 

 and was 34 below the mean rate in the corresponding 

 periods of the ten years 1878-87. The 1,314 deaths 

 included 30 from measles, 22 from scarlet fever, 27 from 

 diphtheria, 13 from whooping-cough, 13 from enteric fever, 

 77 from diarrhoea and dysentry, and not one from small- 

 pox, typhus, ill-defined forms of continued fever, or 

 cholera ; thus 182 deaths were referred to these diseases, 

 being 34 below the corrected average weekly number. 

 In Greater London 3,158 births and 1,634 deaths were 

 registered, corresponding to annual rates of 29-8 and 15-4 

 per 1,000 of the estimated population. In the Outer Ring 

 14 deaths from diarrhoea, seven from diphtheria, and six 

 from scarlet fever were registered. The deaths from 

 diarrhoea included three in West Ham, three in Croydon, 

 and two in Tottenham sub-districts. Three fatal cases of 

 scarlet fever occurred in West Ham, and three of 

 diphtheria in Walthamstow sub-districts. 



