THE NEW NATIONAE STAND AED OE LENGTH, AND ITS PRINCIPAL COPIES. G85 
The following is extracted from the Minutes of the Meeting of the Committee, 1843, 
November 10 “ Mr. Baily reported that he had made trials of various materials for the 
Standards of Length ; namely, steel, brass, and four kinds of gun-metal. One of the 
gun-metals, composed of 28 lbs. of copper to 4 lbs. 6 oz. of tin [I believe that which is 
called No. 4 above, though the statement of the component parts is not quite correct], 
was very brittle, and the bar had been broken in his experiments. The next [No. 3 I 
believe], composed of 28 lbs. of copper to 2 lbs. 10 oz. of tin, was very elastic, returning 
perfectly to its original state after having been sensibly bent by heavy weights ; and on 
being chipped, was found by Mr. Baily and Mr. Donkin to be much less brittle than the 
former. Mr. Baily intimated that he wns disposed to recommend the use of this metal.” 
The following is extracted from Mr. Baily’s MS. book: — “ November 13. — Attended 
at Mr. Simms’s, and submitted the gun-metal bar No. 3 to the same process as on Sep- 
tember 9. After putting 5^ cwt. in the scale, the bar was so much bent that it slipped 
off the support ; and on measuring the curvature it was 4T inches. I then submitted a 
copper bar of the same dimensions to a similar process. After putting 4 cwt. into the 
scale, the bar was bent 3-8 inches.” 
The experiment is farther explained by the following extract of a letter to myself, 
dated 1843, November 15 : — “ I have tried the effect of applying a great weight to the 
bar which Mr. Donkin and myself seemed to prefer to that which had been previously 
tried. The result however has completely altered my opinion. I found that 5^ cwt. 
bent the bar so much that it slipped off the support. The curvature (or versed sine) 
was 4T inches, which was permanent, and did not recover itself. It certainly was a 
tougher metal, which was what Mr. Donkin, and I believe all artists or mechanics, 
delight in. But this is not the quality that suits us ; and I therefore prefer the more 
brittle metal, which was elastic as long as it would hold together, and would rather 
break than bend.” 
Mr. Baily adds : “ Instead of having the ends of the bar cut off as a notch in Katee’s 
mode, I propose to have a cylindrical hole drilled, f ths of an inch in diameter, half-way 
through the bar. I find that I have as much light as on the open surface, and my 
objection to weakening the bar is thereby removed. Mr. Simms says he can cut as fine 
a line at the bottom of this well, as he can on a plane surface. He is trying his hand 
at this experiment, and if it succeeds, I trust there will not be any objection to the 
method. It will be much safer as to strength, and the lines will be well protected.” 
Mr. Baily’s iUness and death prevented him from laying these results before the 
Committee, but I communicated them at the meeting of 1844, November 30. The 
gim-metal No. 4 has been adopted in all the standard bars subsequently made (except 
where a difference is specially mentioned), and it appears to be an admirable alloy for 
all similar purposes. Its exact composition is — 
Copper 16 
Tin 2| 
Zinc . 1 
