522 C. PIAZZI SMYTH ON THE 



spring of 1883-4, with the valuable aid of Messrs T. Cooke & Sons, of York, 

 to adapt my example of a Rowland's grating for use in a large wood and metal 

 apparatus. This was of somewhat unusual form, carried object glasses 4 inches 

 in diameter, employed a magnifying power of 67 times linear on the inspecting 

 telescope, and was specially adapted for securing differentially, but with 

 remarkable rapidity, a highly magnified record of the whole visual solar 

 spectrum, whatever that might prove to be at the epoch. 



Something however still more than one single record of such a spectrum 

 appeared due to the science of our time ; for such science has established most 

 profoundly, that there is no scientific subject of numerical mensuration whatever, 

 wherein any man, or any number of men, can do more, when they aim at 

 exactitude, than arrive within certain limits of probable error as to what the 

 truth may be. As these limits too may be very various for the different lines 

 of the spectrum, of which there are several thousands, — I determined, if I 

 could observe one spectrum well, to follow it up by a second, and even third 

 time of going through the whole of it ; with the view of eventually bringing 

 the three records together in such a manner as to facilitate their comparison, 

 and rather provoke, than silence, criticism on every line. 



But could three such extensive spectra be successively, as well as com- 

 pletely, observed micrometrically by the eye and hand of one observer in the 

 course of two months only of an ordinary North-British summer season ? 



Not unhappily in Edinburgh ; where, over and above the general cloudiness 

 of the summers, the fearful increase of coal smoke in the air, during these 

 latter years of unexampled growth of its happy population in numbers, wealth, 

 and abundant burning of coal without consuming the smoke thereof, — has 

 vitiated the city's atmosphere to a degree quite prohibitive at last of any of the 

 nicer observations of Astronomical Physics. 



Could, however, the desired end be obtained by visiting the South of 

 England, profiting by itsusually sunnier summers, the absence of coal fields, and 

 avoiding the larger cities \ 



That was what I proposed to try; and after some deliberation pitched on 

 Winchester. Once indeed the ancient metropolis of England under her Saxon 

 Kings; but now is it so shrunk within its former magnificent bounds, and so lowly 

 withal, that with the exception of its Cathedral, St Mary's College, and a new 

 town-hall by Gilbert Scott — the rest of its generally diminutive, flint-walled 

 houses might almost all be packed away, even hid, within our George Street. 

 Eminently neat and decorous however is modern Winchester ; with no manu- 

 factories to speak of, save a few small ones for brewing beer, or preparing 

 Hampshire bacon and flower honey. A useful country town evidently for farmer's 

 supplies, and yet grandly historic. Surrounded by healthy, open, undulating 

 chalk downs, with umbrageous trees and charming gardens in their hollows ; 



