The above is not a building on Market Street. I'd guess somewhere on Madison or Henry. Mary instead lived at 43 Market in 1900. Below is part of the census report for that address. Looks like Mary may have had some money. She appears to have a servant. The money must have been "old", because from the census the block is populated with working class types.
from an ancestry message board
I am actually a bit familiar with your family, but just a bit and only very recently. I am from the LaTourette family and I just finished up some basic research for a staff writer for the New Yorker Magazine. They are doing (or thinking of doing) an article on Golf Courses within the NY City limits. This is what I know, and again a bit limited:
From the NYC directory of 1869.
Mairs John Dows, mer. 20 South, h 114 E. 36th (he is a Merchant)
And I also found this today:
JOHN DOWS MAIRS, merchant, who died in Irvington-on-the-Hudson, Oct. 3, 1881, in his 54th year, was a native of Utica, N.Y., and a nephew of David Dows. He began life as a clerk for Mr. Dows, who entertained a sincere respect for his competent young nephew. He was drawn away to California for a time but returned to New York and by invitation of the senior partner entered the firm of David Dows & Co. in 1854. In the affairs of this house, he spent the rest of his life, gaining a fortune and the esteem of the whole mercantile community. He was a member of the Produce Exchange from its organization.
He married a woman by the name of Mary St. John and this is the obit I found on her:
The notice of her death was in the New York Times, 04/30/1906:
Mairs - On Sunday morning, April 29, Mary E. St. John, widow of the late John D. Mairs,
Funeral services at her late residence, 14 West 54th Street, on Tuesday morning, May 1, at 10 o'clock. Kindly omit flowers.
Their son was Edwin Hays Mairs and I believe they also had a daughter named Mary Dows Mairs who married Rev. John Betts Calveret.
Edwin Hays Maris married my distant cousin Catherine LaTourette Evans and they had four children that I know of (I could dig for more information): John Dow Mairs; Mary St. John Mairs; Joanna LaTourette Mairs and Walton H. Mairs.
As you probably know, John D. Mairs was born May 5, 1886, married Feb. 14, 1911 to Mary Dake Mattison, and died May 2, 1928. And I have them having at least three children: Edwin Hays Mairs; Unknown female Mairs and John Dows Mairs. You know the rest.