According to Joseph Jackson's Encyclopedia of Philadelphia, Vol.III, p.682, they were a row of fourteen buildings built by a speculator in 1759, located on the west side of 5th Street above Race. Robinson's 1799 directory lists them as being the even numbers from 130 to 146 North 5th Street (Biddle system of numbering), and so those 1791 listings for N. 5th Street have been repeated here.
Because these listings were on a main street (5th Street) it is curious that MacPherson broke in this instance from his usual practice of using official street names, and even more so that Francis White with his practice of following common usage, does not mention the Fourteen Chimneys. Though this could be explained by White's having had strangers to Philadelphia in mind, who would have only been familiar with the block-by-block system of giving directions, White, in fact, lists none of the inhabitants of the Fourteen Chimneys as given by MacPherson, anywhere in his directory (even making allowances for alternate spellings) under any address.
It may be that these houses were in a sufficiently unusual orientation-- collectively U-shaped, for example-- that MacPherson decided that they were like a separate court or alley.
(1785) #1, Hause, Valentine
(1785) #2, Shryner, Widow
(1785) #3, Donchan, James
(1785) #4, Foulke, Frederick
(1785) #5, Lant, Widow
(1785) #6, Millar, Jacob
(1785) #7, Flucker, George
(1785) #8, Emart, Widow
(1785) #9, Foster, James
(1785) #10, Shitz, Widow
(1785) #11, Eward, Jacob
(1785) #12, Hyde, Anthony
(1785) #13, Syfret, Jacob
(1785) #14, Shefer, Adam
(1791) #130 N. 5th St., Etris, John, grocer & tallowchandler
(1791) #130 N. 5th St., Haney, Conrad, labourer
(1791) #130 N. 5th St., Hess, Nicholas, blacksmith
(1791) #130 N. 5th St., Klein, John, taylor
(1791) #130 N. 5th St., Turniss, George, barber
(1791) #132 N. 5th St., Ebhart, John, labourer
(1791) #132 N. 5th St., Emmerton, Catharine, widow
(1791) #132 N. 5th St., Schwalbach, Henry, cedar cooper
(1791) #134 N. 5th St., Foster, Elizabeth, widow
(1791) #134 N. 5th St., Schranck, Michael, labourer
(1791) #134 N. 5th St., Stahl, Catharine, widow
(1791) #136 N. 5th St., Duffey, James, cordwainer
(1791) #138 N. 5th St., Ewald, Jacob, bricklayer
(1791) #140 N. 5th St., Camper, Jacob, type founder
(1791) #140 N. 5th St., Dice, Margaret, widow
(1791) #142 N. 5th St., Seyfield, Jacob, blacksmith
(1791) #142 N. 5th St., Zorguebel, Godfrey, weaver
(1791) #144 N. 5th St., Camper, Joseph, type founder
(1791) #144 N. 5th St., Vogel, Nicholas, labourer
(1791) #146 N. 5th St., Mecklenburge, Anna Catharine, nurse
(1791) #146 N. 5th St., Mecklenburg, Anna, Margaret, Barbara & Elizabeth, tayloresses
(1791) #146 N. 5th St., Turniss, George, mason