634 
ME. AIET’S ACCOTJ]S’T OF -THE COXSTErCTIO^” OF 
Mr. Baily proceeded immediately to make experiments on different materials, as 
applicable to the formation of Standard Bars. Mr. Baily, I believe, entertained with 
me the opinion that, if a bell-metal or gun-metal mixture could be found possessing the 
properties most essential to the present use of a standard bar, it ■would be greatly pre- 
ferable to iron or steel for the construction of a standard intended to last through many 
ages, by reason of its almost perfect immunity from rust. Therefore, although a bar of 
steel was prepared at the same time as bars of different compositions of gun-metal, and 
though it is expressly recorded that experiments were made on it, they do not appear to 
have been made with the same detail as those on gun-metal bars ; at least I find no such 
details in Mr. Baily’s Manuscript Book or in his correspondence •v^fith me. The entries 
most worthy of note are the following : — 
“ 1843, August 18. — Mr. Simms having procured the five* bars before mentioned [all 
40 inches long and 1 inch square], and also a brass tube, I this day attended at his house 
to make experiments on the curvatm’e of the same, by attaching various weights to the 
cerrtre, when the bar was supported at the ends. The steel bar was the first tried. 
“ August 21. — Attended again at Mr. Simms’s, and experimented on the brass bar Xo. 1. 
“August 23.— -Experimented on the gun-metal bar No, 2. 
“ August 24. — Experimented on the gun-metal bar No. 3. 
“ August 25. — Experimented on the gun-metal bar No, 4. 
“ August 26.— Experimented on the brass tube, similar to Ast. Soc. Standard. 
[It appears, from a letter of Mr. Baily to myself, dated 1843, August 30, that the 
greatest weight was 21 lbs.] 
“ August 31. — Let fall all the brass bars from an elevation of 5 feet on a stone pave- 
ment. The gun-metal No. 4 was the least affected, but none of them broke. 
“ September 9. — Loaded No. 4 at the centre with ^ cwt. weights till the total weight 
was 5^ cwt., when it snapped -with a loud report, like a loud shrill bell %iolently struck. 
It was very elastic whilst the weights were being apphed. [The bar was e-sidently show- 
ing signs of elasticity during the operation, and sprung up and do•v^•n like a piece of 
whalebone ; and I really believe that the bar would have resumed its straightness, if the 
weights had been removed immediately before the last was put into the scale. The 
pieces, on breaking, sprung up, by reasorr of their elastic force. The fi-acture was pre- 
cisely in the middle, which irrdicates the soundness and urrifoirnity of the structur-e, and 
the granulation is very good. As the weight of the scale, ropes, and non hook, must 
have exceeded cwt., the total weight apphed was above 670 lbs. — Letter to myself, 
dated 1843, September 11.]” 
* Messrs. Mavdslaxs and Field, by wbom the brass and gun-metal bars ■were cast, have favoured me 
with the particulars of their composition. They are as foUo'ws : — 
No. 1. Copper 32, zinc 12. 
No. 2. Copper 32, tin 1, zinc 3. 
No. 3. Copper 32, tin 3, zinc 2. 
No. 4. Copper 32, tin 5, zinc 2. 
