TRANSACTIONS OF SECTION E. 739 



wind by a piece of glass floating- on tlie mercury. The liability to errors introduced 

 by this arrangement is much smaller than might have been expected and 

 travellers speak highly of its merits. The appliances for measuring elevation 

 above the sea-level have been greatly improved. The old method was to carry a 

 mountain barometer, which, from the weight of the mercury and the fragility of 

 the glass that contained it, was rarely carried far without breakage. Siu'ce then 

 the aneroid has been invented, and the appliances connected with the boiling-point 

 thermometer have been greatly improved. A traveller provided with these very 

 portable instruments can use the aneroid for everyday purposes, checking its 

 change of index error from time to time by boiling-point observations. Even the 

 mercurial barometer has been rendered a comparatively portable instrument. The 

 tubes are packed empty, and they are filled when required by Captain George's 

 method, which in moderately careful hands is found to give good results. The 

 enclosed thermometer for deep-sea observations is a recently invented instrument 

 absolutely essential to accuracy. 



The art of exploring ocean-depths and performing what has been called 

 Thallassography, has been immensely improved, owing to the requirements of sub- 

 marine telegraphy and of such scientific expeditions as that of the Challengei; 

 Sir W. Thomson's method of sounding at the depth of many fathoms without; 

 checking the ship's course is in full use, but Dr. Siemens' bathometer has not yet 

 been made practically serviceable. 



The accuracy of thermometric graduation has been greatly increased by the 

 verifications afforded by the Kew Observatory, which is the child of the British 

 Association, established, and for a long time maintained, by a yearly grant from 

 its funds, but now supported by the endowment of Mr. Gassiot. The errors in 

 thermometers occasionally furnished even by the best makers in 1830, were such as 

 would not be tolerated now. The verifications of Kew are extended to other 

 instruments, and the influence of the Observatory for good is firmly established and 

 appears to be yearly increasing. Of the other appliances for geographical travellers 

 — such as scales for plotting, metal pens which were invented since 1830, and that 

 admirable recent contrivance the stylographic pen — it is unnecessary to speak in 

 detail. The binocular opera-glass is, practically speaking, a new instrument, and its 

 merits as a night-glass were first found out long after 1830, The lunar tables of 

 the '■ Nautical Almanack ' have been greatly improved of late years, for in 1830 

 their predictions of the place of the moon could not have been trusted as they now 

 are for delicate determinations of longitude. Lastly, the means of instruction in the 

 use of geographical instruments is at length afforded by the Geographical Society, 

 who have erected a small observatory on the roof of their premises, where 

 instruction is given on moderate terras to intending travellers. 



The modern equipment of travellers as regards dress has been greatly improved 

 by the general use of flannel, which is a most important preservative of health, 

 but was neglected half a century ago. Thus, at much more recent times thau 

 1830, the hardy Swiss guides had a horror of what they called a coup-cTair, or a 

 chill on the mountain-top, when they were hot and perspiring ; and no wonder, as 

 they then all wore linen shirts next the skin. The modern loose form of dress, 

 the shooting boots and easy overcoat, are a vast improvement on the pinched 

 costumes of 1830. The derivation of the word paletot conveys a history. The 

 first warm and convenient coats used in England were reproductions long subse- 

 quent to 1830 of those used by sailors in rough weather under the name of ' pilot 

 coats ' (and were sometimes, for the sake of shortness, called ' p. coats ' or ' pea- 

 coats '). They quickly became the fashion, were copied and made more eles:antly 

 by the French, who adapted our name of ' pilot coat ' to their own pronunciation 

 of paletot, and so we received it back from them. India-rubber and gutta-percha 

 adaptations to articles of dress and manufactures generally date from a little 

 subsequent to 1830 ; they are invaluable for many purposes to exploring expe- 

 ditions. The form of tent has been greatly improved. Portable mackintosh and 

 other boats are comparatively recent contrivances, and have done good service, 

 Lucifer- matches had been invented, but only very recently, in 1830. 



The equipment of a travelling party as regards packsaddles haa been improved, 



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