STORM WARNINGS.

Press, Volume VII, Issue 683, 6 January 1865, Page 5

STORM WARNINGS.

The following letter from Admiral Pitzroy appeared in the Tikes of Oct. 7. Sir, —Many of your readers who are interested by the practical results of our recently instituted mode of forewarning maritime interests when stormy weather is approaching ask such questions as the follow■• j n ,r : —" What are the principles on which i storm warnings are given ? " 1 To answer in a few words, and not indistinctly, is scarcely now so difficult as it would have been a few years ago, the writer believes and would wish to prove briefly. Considering atmosphere as fluid, having currents of varying conditions affected by temperature and pressure, always seeking horizontal level, however incessantly disturbed, and hot very many miles in depth,— considering earth's rotation aud effects of solar heat, in addition to those of attraction by moon and sun, and knowing, how the barometer and thermometer indicate changes, we see that observations at several stations telegraphed to a centre may show what are the various states of air, and in ' what direction it is moving, besides other details." _ . Now, as air moves in extensive masses, has excessive elasticity, and much watery vapour, the opposition or combination of its currents in temperate zones occasion all their varieties of climate and season under the sun's influence as principal motor. Practically, then, in forecasting weather, the meteorologic characters of several places; are ascertained and. compared, whence Conclusions are drawn thus :—Wind hlows from, higher toward lower pressure, curves around a space of low pressure. Temperature indicates whence it comes (being higher or lower than usual.) Dryness, also, or moisture, besides showing ditectibrij id sdme degree indicates a change to $dry or a moist., quarter. Windcnangingtotheleffe,,is raihyj; to the right usually dry; and many.other such facts are to be noticed. . >:. i ■-.> But the chief points ar_ relative positions, extent, and width of air currents, as they pass over hundreds of miles. Between them, the southerly'and north* erly, .with their combinations, , there _ T are usually very variable winds, sometimes stormy. - ; d.- ■■=■.■ ' '*.:■:•'j'i As the'limits or margins of these current! have pressures and temperatT_reß*___js or greater than their central lines, and as their width is proportionate usually to their circuitous sweep around the area of low baroriieter; two or three ' stations'--oDse-va. tions usually suffice to show, approximately, what is the character and the tendency fof air- streams, even, considerably beyond the? most distant station; By thus theorizing fbr Temote placesrising actual measures from nearer' ones-*—' comparing high and low quantities north. and south, east and west, by knowing thecourse of wind currents and their eddies (afcitimes storms), we are enabled.»look beyond' Ireland into the Atlantic, ahd obtain noticfc of^changesonly then approaching.., " "'" f*' . Elsewhere it has been repeatedly observed, that bad weather over Ireland precedes that of England s hyabdut a day, and that winds from., eastward are usually or south-easterly, not from east direct. ; .1 PITZBOX-

. Fbbkch , R__lw_*_b_ — A publication recency, issued by the office for railway. statis__. .established at the Ministry of Commerce, Agriculture, and Ppbfio. Works contains some interesting details: The, total length of railway open to the public during the .year 1862 was 52,209 kilometres (five-eighths of a mile each), which produced 2,000,735,707t, oran.avarage of 34,962f per kilometre; The receipts per kilometre in the different countries' of Europe, went aa follows:' — France, _5,781f; Great Britain and Ireland, 40,_17£; Saxony, 37,152f; Austria, 33,709f; Prussia, 30,9 _sf; Belgium, 29,712f; Wurtemburg, _27,068f;. German Duchies, 26,423 ; Russia, 26,075?; Holland, __>,008f; Hanover, 24,007f; Italy, 2_,o6Qf I 21,737f; -Spain, 20,966f; Denmark, ls,2o7F;.Portugal, 9,801f; Turkey. 5,028f;, and Sweden iapicf Norway,. 4,383f: . The coat of ,thi» French lines, consisting of a network 'of ebon* 20,000 kilometres is estimated' at an averagV of 362,950f per kflometre, at the charge of the companies. If-that outlay is compared with the gross receipts of 45,781f per kilometre, which is reduced by the working expenses (about 40 per cent) to to 27,469fj the result willbe that the capital invented in the form of sharesorobttgataoni produces a revenue exceeding 7i per cent Such a return, without being excessive, would be sat_rfactory if the companies could consider it to be definitely, acquired, but such aa illusion is not to be permitted. There still remain 10,000 kilometres to be opened, and admitting tj»a£ they will produce an . average, of 30,000f ncr t_kK metre, this second portion of t_« French network will only leave a clear income of 15,000£ deduction' being made of 50 per cent for the working expensea. the proportion of which increases as the gross receipt* diminiah. So that the net. produce pet kilometre being destined at a future date' to amount' to 21,834. 50c only for the whole of the French network, .that average wOl represent bat 5f Bjso per cent of jjbh capital invested, a rate corresponding exactly with that at which the companies <mfra_ct&ehrld«___* k As to the engagements to a_s_re the executiOTirO. f3cse French line., entered into by the pubKe Treasury, which has to aid the companies in paying the interest on the capital absorbed, when they are unable to do so themselves, tho guarantees granted t<_ the inherent companies may be estimated. asKkefy to anmoMta eight or ten years to 30,000,000? aimu_ny. ThaVA no doubt a considerable sacrifice,; but the gratideur of the jjiisiwd, ' ' ' ../;:',: : , iv M^*_aa, t^