April 1 8, 1872] 



NATURE 



479 



ment of Indian Stations, drawn up by the Army Sanitary 

 Committee. 



The American contrivance produces the same result in 

 duphcate by one fire-place intended to be fixed in the 

 centre of the ward. There are two open fires, one facing 

 each way. The fresh air to be warmed is passed under 

 the floor to the space between the backs of the two fires, 

 and is thence admitted in the room. The arrangement is 

 simple, and ought to be effective. 



It is evident from the reports generally, that much im- 

 provement is required in existing barracks and hospitals 

 in the United States, and that overcrowding, defective 

 ventilation, and other disease causes, still exist there as 

 they used to do with us. It is a great step towards im- 

 provement to have an honest statement of defects. We 

 must congratulate the Surgeon-General's department on 

 the production of these reports, and express our hope 

 that the executive authorities may make as good a use of 

 them as the reporters have done of their opportunities of 

 acquiring information regarding the stations. 



OUR BOOK SHELF 



Scottish Meteorology, from 1856 to 1871. Being a con- 

 tinued monthly and annual representation of the more 

 important mean results for the whole country, deduced 

 at the Royal Observatory, Edinburgh, from the sche- 

 dules of observation by the Observers of the Scottish 

 Meteorological Society, for the purposes of the Regis- 

 trar-General of Births, Deaths, and Marriages in Scot- 

 land. (Edinburgh Astronomical Observations, vol.xiii.) 

 In the Introduction to this work, the Astronomer Royal 

 for Scotland tells us that it was undertaken at the request 

 of Government, the application being to deduce from the 

 observations taken under the auspices of the Scottish 

 Meteorological Society, " certain monthly and general 

 results for each and all of the stations, results supposed to 

 be important for medical climatology and its influence on 

 population and national welfare." The ways of statisti- 

 cians arc mysterious ; it is difficult ttJ understand what 

 advantage either to medical cHmatology, to agriculture, 

 or, broadly, to national welfare, is to be derived from the 

 means here printed, means not only of barometric pres- 

 sure, but of temperature, rain, and hours of sunshine, 

 including as they do the observations at some 55 stations 

 scattered over all Scotland, from the Shetland Islands to 

 Dumfries, from Aberdeen to Islay — places with peculiari- 

 ties of climate as distinct as could anywhere be found 

 within anything like equal distances. We suppose, how- 

 ever, that there is a use for them ; and, that being the 

 case, they could not be put before the reader with more 

 beautiful simplicity and clearness than we here find ; but 

 as we reflect on the enormous amount of skilled labour 

 which the reductions must have cost, we cannot help 

 regretting that meteorology can derive no advantage 

 from it. With this report for "the purposes of the 

 Registrar-General" is sewn up one of a very different 

 and highly interesting character, the detailed observa- 

 tions of the storm which passed over the North of Scot- 

 land on October 3, i860. These observations describe very 

 fully a storm of extraordinary intensity, bursting almost 

 with the suddenness of a meteor on the northern coasts ; 

 with such suddenness, indeed, that at several of the 

 stations where the barometer was registered only at in- 

 tervals of twelve hours, the whole fall, amounting, it would 

 seem, to about l"8in., and the subsequent rise, passed 

 quite unnoticed. One point which has been often, though 

 not very closely, observed in tropical cyclones, comes out 

 most distmctly — the remarkable rise of the barometer 



beyond the limits of the storm, before and after it, in Scot- 

 land, in England, and France, about the timeof itsmeridian 

 passage. The lowest barometric reading anywhere ob- 

 served was 28 5 ; this leads us to remark that, in tabulat- 

 ing the conclusions, the force of the wind has been unin- 

 tentionally much exaggerated, owing, it appears to us, 

 to a confusion common to all non-nautical minds between 

 the land scale, which numbers from o to 6, and the Beau- 

 fort, or sea scale, which numbers from o to 12 ; for the 

 one is not to be converted into the other by simply 

 doubling ; and the shore 6, far from being the equivalent 

 of the Beaufort 12, is more nearly represented by 9 to 10, 

 or at the outside by 10, which may be considered as cor- 

 responding to a velocity of about 80 miles an hour. In 

 the discussion of the observations of this storm, many 

 points of great interest arise : amongst others, the rela- 

 tionship between wind and pressure, the howhng of the 

 wind, and the ascensional motion of the air near the 

 centre. The curt, able, cautious, and suggestive treatment 

 of these is such as we might expect from the high standing 

 of Prof. Smyth, and leaves little to be wished for except 

 time for meditation. J. K. L. 



The Devintioii of the Compass in Iron Ships considered 

 practically for Sea Use, and for the Board of Trade 

 Examinations. By W. H. Rosser. ("London : Long- 

 mans.) 

 In this small treatise the Deviation of the Compass in iron 

 ships is professedly dealt with as a matter of observation, 

 and distinct generally from magnetic science and the 

 mathematical investigations based thereon. Mr. Rosser's 

 long experience both as a " teacher " of officers in the 

 mercantile marine, and an adjuster of compasses for the 

 ships of that service, has enabled him to produce a work 

 calculated to give those with whom he has been so long 

 associated good practical information. The articles on 

 the compass equipment of ships and the heeling error are 

 judiciously given, and rightly occupy a prominent place. 

 Whilst, however, thus commending the work, it must be 

 regarded as meeting only a present and passing want ; 

 for from the absence of many theoretical, but not neces- 

 sarily abstruse, details, the subject even as presented from 

 a practical point of view cannot be considered as grasped 

 with that entirety which certainly belongs to it. Those 

 theoretical deductions which have been practically con- 

 firmed are further requisite in the advanced examinations 

 instituted by the Board of Trade, and are, moreover, to 

 be found in the several manuals compiled under the Ad- 

 miralty and Board of Trade auspices. 



LETTERS TO THE EDITOR 



[The Editor does not hold himself responsible for opinions expressed 

 by his correspondents. No notice is taken of anonymous 

 communications. ] 



Error in Humboldt's Cosmos 

 I BEG to call the attention of geometers to what appears to 

 me to be an inaccuracy in a work, which is, perhaps, the last 

 which one would suspect to be capable of error — the " Cosmos " 

 of Humboldt. 



In vol. i. p. 293, he says, "I have found by a laborious in- 

 vestigation, which, from its nature, can only give a maximum 

 hmit, that the centre of gravity of the land at present above the 

 level of the ocean is, in Europe, 630 ; in N. America, 702 ; in 

 Asia, 1,062 ; and in S. America, 1,080 French feet (or 671, 7*48, 

 1,132, and 1,151 English feet) above the level of the sea." Sir 

 John Herschel in his " Physical Geography " (Encylop. Britt.) 

 quotes these numbers of Humboldt as giving the height of the 

 centre of gravity of these continents ; and adds, " whence it fol- 

 lows, that the mean elevation of their smfaccs (the doubles of 

 these) are respectively 1,342, 1,496, 2,264, and 2,302." Heischel's 

 conclusion is, of course, just, if Humboldt meant what he seems 

 to say. But at the risk of being thought most presumptuous, I 

 submit that Humboldt meant the height of the centre of gravity 

 of the surface of the land ; in other words, the mean height of 



