JF Ptak Science Books Post 2307
Here's an extraordinary find, a bump in the grazing field in the Scientific American Supplement for January 19, 1878. The article is about dust--but not the cosmic dust that some folks say is what is being seen in the Big Bang (and not a background radiation signature), nor is it like the dust equation nor the dust of Einstein's great dust paper of 1905. It is more like a lower-level plague dust as we see in Arthur Rothstein's iconic dust bowl photograph made in parched Oklahoma in 1936. It is about the residue of industry and commerce that did't get carried of by the mysterious carry-off winds associated with the high and higher chimneys of Victorian London and other industrialized cities, and the leftover bits of the operation of daily cosmopolitan life involving say horses and trains. It is an article about the significant particulate matter of dust, which we know today is a high-percentage contributor to air pollution, not to mention the low-level "atmosphere" of the kicked-up business that people would breathe in every day.
And, evidently, this dust was very heavy-metal rich in composition, which is not so good.
The article is "Street Dust", and the author, Henry G. DeBrunner (who would become professor of chemistry at the Pittsburgh College of Pharmacy), decided to take a look at the dust of Pittsburgh and compare it to reports of the dust of major European cities. He notes that Paris and London and other cities consist of 35% of "metallic iron, given by the shoes of horses to the stones, besides from 30 to 40% of good glue from the hoofs". Now that seems an extraordinary figure, and surprising too in many ways that it came from horse shoes.
[Source: an advertisment from Scientific American, volume 79, 7 January 1893, back wrapper.
DeBrunner conducted a study at Thirtieth and Smallman Streets (Pug) and found out that 30% of the sample of dust ("a deep black color") consisted of silic acid, 26% of "fixed carbon", ferric oxide at 12%, sulphuric acid at about 1%, gluten 1%, Metallic iron 8.55%. The details of how all of this was extracted can be seen below, where the entire article is reproduced. There were other samples, and it is interesting to note that in one sample near horse tracks contained 32% heavy metal and lots of glue.
The entire article, January 19, 1878, Scientific American Supplement, No. 107: