374 Eighth Memoir on the [No. 137- 



The indications of scarcely any two barometers exactly agree; and 

 betwixt the tropics, where the total range scarcely exceeds three- 

 tenths of an inch, the most delicate movements of the mercury must be 

 watched. In marine barometers, besides, the correction for the rise 

 of the quicksilver in the cistern can very rarely be made with any 

 approach to accuracy, and scarcely ever, in any two instruments, how- 

 ever similar, precisely corresponds. It depends upon the relation of 

 the diameter of the tube to that of the cistern, the latter varying not 

 only in different instruments, but in different portions of the same: 

 this invariably makes the observed depression less than what it ought 

 to be. It is still worse with the sympiesometer, whose indications of 

 pressure are so complicated by high temperatures, that unless to 

 those long familiarized with it, it is of little value between the 

 tropics. These imperfections would in a great measure be re- 

 medied, were the observer in possession of a schedule of corrections 

 which he could at any time apply. These considerations, if considered 

 of value, might be tested here by the Indian Navy ; and we have no 

 doubt would be productive of important results. The instruments, 

 indeed supplied by the Company, especially the thermometers, are often 

 of such indifferent quality, that unless rated or corrected, they are com- 

 paratively of little use. Instead of lumbering about amongst arsenal 

 and naval stores, they ought to be placed where they could be taken 

 care of and kept in order ; where their excellencies could be pointed 

 out, and their imperfections remedied. It would appear incredible 

 were it stated, that the efficiency of a very able and experienced en- 

 gineer corps is in many cases neutralized by the wretched economy 

 that refuses to supply instruments fitted for service ! Yet we have 

 been told of an extensive district under the supervision of a very able 

 officer, where levelling and general surveying is constantly required, 

 where there is not a level or theodolite fit for the common purposes of 

 road-making; and where, in consequence, the services of highly-gifted 

 and well-paid officers are impeded or thrown away for a consideration, 

 which would not amount to a single week of the pay and allowances ! 

 The Madras gale was encountered by the Seaforth Ceylon steamer 

 off Cochin, at 10 p. m., on the 25th ; it dismasted the Lucy Wright, 

 near Man galore, on the 26th ;* the Futtay Salam, from Calcutta, was 

 overtaken and nearly swamped by it, close to the Laccadive Islands ; 

 * In the following extract it is said on the 27th. 



