1836.] 



Abstract of Meteorological Tables. 



817 



advantage, however, of the plan of parallel lines was, that type might 

 be adapted to express the observations with as much facility as to a 

 figured statement. Having the brass rules of my calendric scales 

 already divided according to the days of the year, it only would be 

 requisite to cast a quantity of rules of the thickness of one day, and 

 exactly one-tenth of an inch in breadth ; the printing surface of some 

 being retained of the full length, and that of others reduced succes- 

 sively one hundredth, two hundredths, three hundredths, &c, so that 

 nine varieties, and a large supply of blanks or quadrates of the same 

 dimensions, would be sufficient to lay off any series correct to the 

 hundredth of an inch, which is ample for most purposes. I here give 

 a sample of this mode of registry in type, although, as I had previous- 

 ly engraved a copper-plate divided for the purpose, I have not, on the 

 present occasion, made any use of the typographic plan, in spite of the 

 far greater expedition and precision of which it is capable. 



Jul 





Mad 



ras. Calcutta. Tirh 



it. Cawnpore. Simla. 



Nipal 



30.0 29 



5 29.5 29 



29.0 23.0 



25.0 



iy- m 



1 1 1 1 



1 1 1 1 



till 



1 1 1 1 



1 1 1 1 



1 1 



5 -1 















Hr 



10 -= 



15 -^f| 



20 r= 

 25 -1 

 30 — 



IE. 



T=. 



: , "^=r ' 



•==. 



~«> ■ 





►■SBj^ 



"j=- 





^■% 



J 



? ^ : 





"~3=. 



It is merely necessary to denote by figures at the top, the value of 

 the neutral line from which each set of readings is to be estimated right 

 and left, in some even division of the inch, as 29.50 inch for Calcutta / 

 29.00 inch for Tirhut, or 25.00 for Nipal, &c. To reduce the lines into 

 figures when requisite, an ivory inch scale may be applied, but this 

 will seldom be necessary if such linear tables are accompanied by 

 monthly abstracts in the ordinary form : the chief advantage of the 

 lines being to shew at a glance the variations of pressure or other 

 phenomena, during the month, in a very small compass, and for many 

 localities at the same time. 



Having thus explained the principles upon which the accompanying 

 plate was filled up, — a work of no small patience by the way, seeing 

 that it contains 13 columns of 365 double entries, or nearly 10,000 

 individual measurements laid ofFby scale to the hundredth of an inch, — 

 I will proceed to notice, first, the authorities whence the various 

 columns are derived ; and, secondly, the instructive and highly curious 

 facts it discloses. 



The Madras column is extracted from the registers published by 

 Mr. Taylor, the H. C.'s Astronomer at Madras, in the Journal of the 

 Literary Society at that place. For the Bombay column I am indebted 

 5 o 



