136 BULLETIN 414, U. S. DEPARTMENT OF AGRICULTURE. 
they are much more expensive than wooden structures, somewhat 
heavier, inconvenient to replace in case of breakage and deteriora- 
tion, hot in summer and cold in winter. When made principally 
of wood they are less expensive, much cooler in summer, lighter and 
easier to move and handle, but subject to damage or destruction by 
fire, more difficult to keep clean and free from vermin, and with 
shorter lives than metal buildings. 
Whatever material be used in the construction, the following 
desirable features should be embodied in the design: 
(1) The sections of which the building is composed should be of 
such size as to permit convenient hauling and erecting. They 
should not be too large for transportation on an ordinary wagon bed, 
and in weight they should not exceed approximately 200 pounds, 
the maximum weight which can be handled successfully by two men 
in erecting and tearing down. 
(2) The sections should be so designed and the connections so made 
as to secure the maximum of flexibility in the building and permit 
ready reduction or increase in capacity to accommodate any number 
of inmates. 
(3) All parts and sections should be constructed by template or 
pattern, in order that similar parts may be absolutely interchange- 
able. 
(4) All units should be so simple in design that they may be con- 
structed by relatively inexperienced labor. Complicated joints, 
irregular shapes, and difficult cuts should be avoided. 
(5) All the parts should be so-called stock articles or easy to impro- 
vise, in order that the cost may be reduced to a minimum and that 
renewals may be made with the greatest ease. 
Stock buildings of either metal or wood, embodying the above 
desirable features, may be purchased from a number of manufac^ 
turers in various parts of the United States, or they may be very 
readily constructed by the regular convict force under the leader- 
ship and supervision of a good carpenter. The latter means probably 
will appeal more strongly to prison officials, as the convict labor 
usually is available for the work, and by employing it the buildings 
can be constructed at a lower cost than they can be bought. 
For the assistance of communities in which it is desired to erect 
buildings of this character, the Office of Public Roads and Rural 
Engineering is prepared to furnish upon application complete de- 
tailed plans and specifications of the portable building shown in 
Plate X, figure 1, the general plans of which are given in Plate XI. 
In the preparation of these plans careful attention has been given 
to all the featurres mentioned above as desirable. The sections are 
designed for rapid erection of buildings 18 feet square, or, by pro- 
