opening
on a hall, or a skylight covered over at the top, "the outer air."[24]
Of these things there is an end. The air shaft that was a narrow slit
between towering walls has become a "court," a yard big enough for
children to run in. Thirty per cent of the tenement-house lot must be
open to the sun. The double-decker has had its day, and it is over. A
man may still build a tenement on a twenty-five-foot lot if he so
chooses, but he can hardly pack four families on each floor of it and
keep within the law. He can do much better, and make an ample profit, by
crossing the lot line and building on forty or fifty feet; in
consequence of which, building being a business, he does so. In a lot of
half a hundred tenement plans I looked over at the department yesterday,
there were only two for single houses, and they had but three families
on the floor.

[Footnote 24: Report of Tenement House Commission of 1900.]

So it seems as if the blight of the twenty-five-foot lot were really
wiped out with the double-decker. And no one is hurt. The speculative
builder weeps--for the poor, he says. He will build no more, he avers,
and rents will go up, so they will have to sleep on the streets. But I
notice the plans I spoke of call for an investment of three millions of
dollars, and that they are working overtime at the department to pass on
them, so great is the rush. Belike, then, they are crocodile tears.
Anyway, let him weep. He has laughed long enough.

[Illustration:

1. Old Knickerbocker dwelling.
2. The same made over into a tenement.
3. The rear tenement caves.
4. Packing-box tenement built for revenue only.
5. The limit; the air shaft--first concession to tenant.
6. The double-decker, where the civic conscience
began to stir in 1879.
7. Evolution of double-decker up to date.
8. Prize plan of Tenement House Exhibition, 1900
(fifty-foot lot).]

[Illustration: Plan of a Typical Floor in Class First of the Competition
in the C. O. S. Plans of Model Tenements.

Rentable area 2724.94^o = 54.70% of lot
Free air-space (courts) 1500.25^o = 30.01% of lot
Walls, partitions, and public space 764.81^o = 15.29% of lot
Total 5000.00^o = 100.00% = lot

3 two-room apartments
3 three-room apartments
2 four-room apartments

8 apartments. 23 rooms]

As for the rents, he will put them as high as