704 PROF. C. p. SMYTH ON THE REPUTED METROLOGICAL SYSTEM 



have only to add the Colonel's own account of the proceedings, and here give his 

 final result : viz., that 45 inches of the Elizabeth ell are equal to 45 0386 inches 

 of the modern legalized, but erroneously derived, British standard yard. That is, 

 Colonel Strange confirms Graham's result within -003 of an inch : and shows, that 

 each of the ell's inches still come within so small a quantity as 0*00013 of an 

 inch to one of the original Pyramid and earth-commensurable inches of the early 

 ages of the w^orld ; of which very trifling difference too, one-half may be due to 

 shrinking of the old scale — made in a material which standard scales never 

 should be made in — between 1743 and 1864; while something more should be 

 allowed for the time preceding. 



Report above alluded to, as received from Colonel Strange, F.R.S. 



ExcHEQUEH, August 3, l&6i. 

 Experiment 1. 



Compared Exchequer secondary standard yard No. 45 with Simms's horizontal comparator, 

 by means of a T square, and found no difference equal to thickness of a line of the graduation on 

 the comparator. Thermometer 69° Fahr. 



The comparator is a fixed graduated brass scale, with adjustable gun-metal table underneath it. 

 It is taken as a standard yard at 62°. It is not intended for the most refined purposes. Messrs 

 Simms say it can certainly be depended on to less than (0001) one thousandth of an inch. 



The secondary yard No. 45 is an end measure of Baily's metal, with spherical agate extre- 

 mities. It is taken as standard — 0-0000639 inch at 62°. 



The above experiment was tried in order to test our means (the T square) of comparing an end 

 with a line measure. 



Experiment 2. 



Queen Elizabeth's yard was compared with No. 45 (above referred to) in Simms's vertical 

 comparator, and found = No. 45 —(5^) one fifty thousandth of an inch. Thermometer 69°. 



The yard has been broken and mended, the joint being loose. It is a very rough piece of work- 

 manship, and the above close result of course was due to the accidental use of a particular spot on 

 the extremities. 



The vertical comparator supports the yard measure under trial in a vertical position. A fine 

 spirit-level resting on the upper end of two yards alternately tried, indicates their relative lengths 

 in terms of the level scale, the value of whose divisions is known. 



Experiment 3. 



An oak rod (specially made for the purpose), provided with a fixed brass stud at one end, and 

 longitudinal spherical-headed screw at the other, was adjusted (by moving the screw) to fit the bed 

 of Elizabeth's ell. The rod and ell were then laid side by side, and compared by means of two T 

 squares. No difierence could be detected with the help of a hand magnifier. 



The bed is of some copper alloy. Its dimensions are, long 4 feet 12 inch, wide r5 inch, thick 



a 



l"l inch. A transverse section is of this form 



id. 



The excavations a and b (nominally 



rectangular) constitute the beds of the ell and yard respectively. They are of the roughest work- 

 manship, apparently executed with a cold chisel. 



