GESERAL REMARKS.] 



METEOROLOGY. 



1171 



excepting when one of these days occurred on Sunday, 

 then to substitute for this date the 22nd. The observa- 

 tions to commence at 6 A.M., and terminate at 6 A.M. 

 next morning. 



Thermometers should be frequently compared with a 

 standard instrument, in order to ascertain whether the 

 freezing-point has remained at the temperature as marked 

 off on the scale. It is a well-known fact, that the zero 

 point moves ; this has been ascertained from the circum- 

 stance that, after a great change in temperature, the glass 

 requires a considerable time to enable it to return to its 

 normal condition. 



NEWMAN'S STANDARD BAROMETER form of Rutherford's 

 thermometer differs in the following manner from that 

 already described : A platinum tube is drawn over a 

 steel wire, which is said to prevent the index from fixing 

 by oxidation. Not having had this instrument at work, 

 we are unable to speak of its advantages from practice. 

 A yood improvement has also been accomplished with 

 Negretti and Zambra's rain-gauge. We conceived it was 

 liable to have the water in the canal surrounding it 

 emptied into the graduated glass with the rain to be 

 measured. At our suggestion this has been altered ; 

 the canal is now placed much lower down the gauge, and 

 there seems 110 possibility of an erroneous measurement. 

 The gauge may, therefore, be now said to be perfect. 



Of late years two new barometers have appeared viz. , 

 the Aneroid and Burdon't. They are both good indicators 

 of atmospheric pressure, but cannot take the place of a 

 Standard barometer. In the first place, the metal is 

 influenced by temperature ; and in the second, there is a 

 chance of the box of the Aneroid and the tube of the 

 Bourdon losing their vacuum. As a household instru- 

 ment, when extreme accuracy is not essential, they aro 

 preferred to the common wheel barometer.* 



At the time of the Great Exhibition of 1851, when tho 

 jury were examining the meteorological instruments, a 

 remark was made that a more perfect maximum ami 

 minimum thermometer was required, both of which 

 should be iiurcuriiU ; and on the council medal being 

 presented to Messrs. Negretti and Zambra, their attention 

 was called to this suggestion. Not many months had 

 elapsed before the patent maximum was produced, and 

 within four years the patent minimum. The latter was 

 sent for trial to a few meteorologists about that time, and 

 one of these instruments came to the Beeaton Observa- 

 tory. The experiments made with it have been perfectly 

 successful ; indeed, so much so, as to have astonished all 

 who have used it. The ordinary minimum thermometers 

 do not work uniformly with this new instrument, owing 

 to the alcoholic vapour contained in the upper portion of 

 their tube, and which is more or less developed according 

 to the temperature. Two such important improve- 

 ments have not taken place since tho invention of the 

 thermometer ; and it is creditable to them that both 

 should have emanated from the same persons who 

 invented the enamelling of fine tubes. 



Professor C. P. Smyth, the Astronomer Royal of 

 Scotland, has caused tho electric telegraph to work in 

 meteorology. A wind dial at the one extremity of a 

 wire, is made to turn another simultaneously at the other 

 extremity. The time will come when all large towns 

 will have buildings devoted to these observations, and in 

 which dials will lie seen in cvury direction, some labelled 

 "Edinburgh, "others "Liverpool," "Dublin," "London," 

 " 1'iti-is," " \ork,"<kc., and where the public will be en- 

 abled to see the direction of the wind at the same instant 

 at most remote places. The benefit to the fai mer and tin; 

 navigator will be great from such an arrangement. Were 

 such stations to be thickly scattered throughout the 

 country, every change of wind, and every shower, could 

 be traced and recorded, and a knowledge imparted, the 

 benefit of which could not be sufficiently appreciated. 



To be enabled to announce the approach of a thunder- 

 storm, however, at a time when the sky is free from 

 clouds, and to ascertain its speed so as to foretel when 

 See Mr. Glaiiher'i report in the next chapter. 



it may be expected in any given place, would afford tho 

 farmer an opportunity of so benefiting by the infor- 

 mation, that he would gladly pay a small rate in order to 

 take advantage of it. The world is slow in appreciating 

 any new invention until its usefulness is experienced : 

 let us, however, hope that such invaluable stations may 

 speedily be established, and we venture to predict that, 

 at no very distant period, every conspicuous eminence 

 will have its road station, to impart the information 

 collected at the principal establishments, where the 

 electric wires are made to record the changes as they 

 occur. Of late years considerable progress has been made 

 in this direction. Admiral Fitzroy has accomplished much 

 by the "forecasts" he has daily published ; and has largely 

 benefited our seafaring popul tion, by "warnings" com- 

 municated to the various seaports. (See following chapter). 

 It is a common expression that nothing is more change- 

 able than the weather ; yet that all these changes are 

 governed by certain laws, is as certain as that gravitation 

 binds the heavenly bodies together. Were there no 

 laws to keep the changes within certain limits, we should 

 at one period experience cold, and at another heat so 

 intense, that existence would be intolerable ; the earth 

 would be deluged with rain, and anon parched up with 

 drought ; the sky would be cloudy for months, perhaps 

 years together, and then cloudless for as long a period ; 

 in short, the laws which govern the weather, keep the 

 extreme changes within proper bounds. 



As the more complicated machinery of a meteorological 

 observatory cannot bo expected to be found except in our 

 principal establishments, it will be requisite to mention 

 what instruments are absolutely necessary for the or- 

 dinary observer. These are A standard barometer ; a 

 wet and dry bulb thermometer ; a maximum and a 

 minimum thermometer ; a rain-gauge ; an evaporator ; 

 a thermometer-stand ; a wind-vane. These would cost 

 from 17 to 30, according to which barometer is 

 selected. The following additional instruments are also 

 desirable (the expense would be 4 or 5): The solar 

 and terrestrial radiation thermometers ; Glauber's elec- 

 trometer : an ozonometer ; and an extra rain-gauge. 



S.VOW-GAUOE. The gauge used at Beeston obser- 

 vatory consists of a thin metal cylinder, eight inches in 

 diameter, and twelve inches deep, graduated upon one 

 side to a quarter of an inch. This cylinder will pene- 

 trate through the snow, scarcely disturbing it, and the 

 depth in inches is at once seen. By careful manipulation, 

 if the cylinder be turned round, all the enclosed snow 

 can be lifted from the ground. It is desirable to melt 

 it in a wide-mouthed bath, the gauge being previously 

 kept corked to prevent evaporation. It frequently 

 happens that snow is blown out of tho mouth of tho 

 rain-gauge before it has had time to melt ; consequently, 

 tho result of melted snow, as shown by the rain-gauge, 

 will be too little in amount. 



CALENDAR OF NATURE. Every meteorologist should 

 endeavour, as much as possible, to record the arrival and 

 departure of migratory birds, the dates of trees coming 

 into and losing their leaves, the blooming of plants, the 

 ripening of fruit and seeds, the building of birds'-nests, 

 the first appearance of various insects, diseases amongst 

 animals and plants, the appearance of abundance or 

 otherwise of crops of fruit, corn, ifec. If such registers 

 were extensively kept and carefully recorded, the effect 

 of the weather upon the animal and vegetable kingdoms 

 would be well seen. It is extremely desirable that every 

 precautijn should be taken, in order that, year after 

 year, the same object should be the special one on which 

 the remarks are based, and that one species be not mis- 

 taken for another. The following examples will show 

 that it is essential to use the utmost care : 



First, ' ' the elm is said to lose its leaves on a certain 

 date." Such an observation is useless. It is requisite to 

 mention the particular kind of elm ; thus, the broad leaf 

 elm is the first tree to become leafless, which it frequently 

 does in September ; the Siberian elm, on the contrary, 

 will remain green after all other trees have become 

 leafless sometimes it is in leaf as late as December. It 

 will also be found that the same species, in a group 



