My question is very narrow and specific:
I am looking for records on value of imported goods unloaded at Northern ports (predominantly NY) and subsequently transported to South and sold to Southern customers.
I am not sure if these records exist or are available. Perhaps I am too perfectionist: in the article I am working on, I already proved beyond the reasonable doubt that tariffs were not nearly the reason for secession and war; now I am going for unreasonable doubts.
I already gave up to find the answer on my question myself; if nobody would be able to help me, article would go as is, with contemporary eyewitnesses opinion instead of numerical data. I think it is good enough, however it could be better.
UPDATE Folks, I have to clarify my question. Post is very long, and it looks like question itself is not clear.
I am not asking if tariffs were the reason of secession and war; l know they were not. The most convincing evidence is not confederate constitution, not historical votes on customs and slavery, and even not secession declarations. The hardest evidences is that in all compromise proposals, congressional and peace conference, there are no single word about tariffs - only slavery, slavery, and slavery.
I am not asking what portion of tariffs was paid by southern ports - 8% I quoted is well supported by census data and other reputable records.
P.S. Thank you to NSNoob for editing this post and making it more readable.
Preliminary research
Proponents of tariffs as primary cause of the Civil war claim:
"Since they were so dependent on trade, by 1860 the Southern states were paying in excess of 80 percent of all tariffs” The Real Lincoln: A New Look at Abraham Lincoln, His Agenda, and an Unnecessary War; by Thomas J. DiLorenzo, 2002, ISBN 0-7615-3641-8, page 135-126:
“During the 1850s, tariffs amounted to 90 percent of federal revenue. Southern ports paid 75 percent of tariffs in 1859” Was the Civil War about tariff revenue? By Walter Williams - Washington Examiner 2/19/13
It is relatively easy to verify that Southern ports paid much less. According to “Financial Failure and Confederate Defeat” by Douglas B. Ball, in 1860 out of total $52.3 million custom collection, southern ports paid $4.0 million (7.6%).
However, it should be considered that because some supplies from overseas were landed in New York and then carried south, southerners as final consumers indirectly paid bigger than 8% portion of tariffs (by no mean 75-80%).
Most likely South paid no more than proportional (by white population) share of tariffs, and probably less, according to contemporary eyewitnesses:
*“When the valued exports and imports of any of the Southern states are compared, it is found that the former is invariably exceeds the latter, in consequence of the want of a consuming class… It is common theme for the Southern politicians to lament the want of enterprise among the merchants in conduct a foreign import trade… But the truth is, there are few imports required, for every Southern town tells the same tale” North America, its agriculture and climate, by Robert Russell, Edinburgh 1857
“A very large part of our duties are collected on the class of goods for which there is almost no demand at all from the South, either directly or indirectly – woolen and fur goods, for instance; of the goods require for the South not a few have been practically free. The whole slave population of the South consumes almost nothing ... The majority of the population habitually makes use of no foreign production except chicory, which, ground with peas, they call coffee. I have never seen reason to believe that with absolute free trade the cotton States would take a tenth part of the value of our present importations. And as I can judge from observation of the comparative use of foreign goods at the South and at the North, not a tenth part of our duties have been defrayed by the South in the last twenty years” The Cotton Kingdom, Vol. 1, by Frederick Law Olmsted, New York – London, 1861
It sounds very logical, and both authors intensively traveled South in mid-1850. However, I prefer numbers, not just impressions. I could not find data to prove (or disprove) this.
Could someone help?