the 2 pole chain was to be 33.03 feet long.
True. It could also be a ton of other things. Mr. Skelton said VERY eloquently in his book (I'm paraphrasing) that when retracing another surveyor, it was VERY important to "adjust your chain" to retrace the previous surveyor.
Huh? Wut you talkin' 'bout, Willis?
I'm thinking one of the manuals said the chain should be long so you didn't pull so much tension and stretch it.
Here you guys go again, chasing 0.04'.
I think that nowadays it depends more on the line thickness on the GIS map they got from the county. I think it's in there somewhere...
But to answer the question, I'll just suggest that "it depends" on what that other guy did. So I'll go with a very definitive positive maybe.
False. The 2 pole chain was exactly 2 poles long.
> the 2 pole chain was to be 33.03 feet long.
I've never had the opportunity to test a chain vs. a standard, but I'll wager that 99 out of a 100 of them vary by more than 0.03'.
I refer ally'all to pages 19&20 of. The Instructions to Surveyors General 1881.
Albert White's History of the Rectangular Survey System on page 515 quotes instructions of 1881:
8. The township lines and the subdivision lines will usually be measured by a two-pole chain of 33.03 feet in length ...
On uniform and level ground, however, the four-pole chain may be used. ... The four-pole chain must be adjusted to lengths of 66.06 feet.
The object in adding six-hundredths of a foot to the 66 feet of a four-pole chain is to assure thereby that 66 feet will be set off upon the earth's surface without the application of a greater strain than about 20 pounds by the chainmen, thus providing for loss by vertical curvature of the chain, and at the same time avoiding the uncertain results attending the application of strains taxing its elasticity.
So this was an allowance for measurement technique, and the goal was still to have 5280 feet per mile to the best of their ability.
The instructions of 1855 call for 33 ft 2-pole chain. I haven't searched any other instructions for similar statements.
It seems odd to me that the allowance for sag at the same tension was only proportional to length. Surely someone knew the formula I find in old books:
Correction (ft) = (w^2 L^3)/(24P^2)
where w = weight of chain per foot, L=feet between supports, and P=pull in pounds
A chain twice as long would have a sag correction 8 times as much.
It depends...
Here is a scan from my original 1881 Manual:
Page 19
Page 20
But I believe that the 1881 Manual is the ONLY one that contained that statement (but I am often wrong too).
Loyal
Most of the chains in my local townships measured about 66.5 to 66.7 feet. I've seen notes in several places where later GLO guys measured across a previous Township or Range line and then adjusted their chain to fit for the subdivision. I think the first surveyors in the area must have added a link. It's pretty hard to measure long with a proper chain length.
One of those trick questions to put on an exam. It depends upon the era or the instructions in place.
I believe there was some discussion about either the curvature of the earth or the ability of a chainman to fully support the chain the entire distance. In a mile the distance would be 4.80' short, so by adding the .06 it would hopefully make things all work out and they did not want to be purposely short because that would naturally mess up the attempt to create 640-acre sections.
The "Standard", from which all of Mississippi territory was gaged/ measured, which includes what it now Alabama, was long. A "normal" quarter of 2640' should measure about 2645', or about an inch and a half per chain.
I'm going from memory, so it may not be exactly right.
So, the answer is, it depends, which is our typical classic answer.
