rty feet in the one
central and two side aisles. The avenues are each ninety feet in
width, and the aisles sixty, with a space of fifteen feet for free
passage in the former and ten in the latter. A transept ninety feet
broad crosses the main building into that for hydraulics, bringing
up against a tank sixty by one hundred and sixty feet, whereinto
the water-works are to precipitate, Versailles fashion, a cataract
thirty-five feet high by-forty wide.

The substitution of timber for iron demands a closer placing of the
pillars. They are consequently but sixteen feet apart "in the
row," the spans being correspondingly more contracted. This has
the compensating advantage, aesthetically speaking, of offering more
surface for decorative effect, and the opportunity has been fairly
availed of. The coloring of the roof, tie-rods and piers expands over
the turmoil below the cooling calm of blue and silver. To this the
eye, distracted with the dance of bobbins and the whirl of shafts, can
turn for relief, even as Tubal Cain, pausing to wipe his brow, lifted
his wearied gaze to the welkin.

Machinery Hall has illustrated, from its earliest days, the process of
development by gemmation. Southward, toward the sun, it has shot forth
several lusty sprouts. The hydraulic avenue which we have mentioned
covers an acre, being two hundred and eight by two hundred and ten
feet. Cheek by jowl with water is its neighbor fire, safe behind bars
in the boiler-house of the big engine; and next branches out, over
another acre and more, or forty-eight thousand square feet, the domain
of shoes and leather under a roof of its own.

Including galleries and the leather, fire and water suburbs, this
structure affords more than fifteen acres of space. Over that area it
rose like an exhalation in the spring and early summer of 1875. At the
close of winter it existed only in the drawings of Messrs. Pettit &
Wilson. Under the hands of Mr. Philip Quigley it was ready to shelter
a great Fourth of July demonstration. This matches the rapidity of
growth of its neighbor before described. The Main Building, designed
by the same firm, had its foundations laid by Mr. R.J. Dobbins,
contractor, in the fall of 1874, but nothing further could be done
till the following spring. The first column was erected, an iron
Maypole, on the first day of the month of flowers, and the last on the
27th of October. Three weeks later the last girder was in place. All
had been don