is placed in inaccessible places. This can sometimes be corrected with concrete.

A painting program would include the painting of small bridges in scattered positions every three or four years. If the territory is extensive, it should be divided into sections, one of which should be included each year. While there are many good proprietary paints, there is no very satisfactory way of selecting them on a competitive basis; and we have found it better to purchase' the paint under specifications upon which all manufacturers can bid.

Dark paints seem to be more durable than light paints; and bridges which are lighted at night can be painted black or some other dark color. Bridges which are not artifically lighted at night should be painted a light color to make them more readily visible. Rather than paint the entire bridge a light color, the floor system and all parts below the usual line of vision (parts where it is generally most difficult to maintain paint) may be painted dark. When a new floor is put on, the. tops of all floor beams, side-walk brackets, and stringers, and other parts ordinarily inaccessible but made accessible during this work, should be thoroughly cleaned and painted. This sometimes involves a hardship by causing delay in the work when traffic is maintained; therefore, instead of two coats of paint, a heavy coat of red lead paste can be used. If creosoted lumber is to come in contact with steel, the ordinary paint will not stand, as creosote is a solvent; hence the finishing coat should be a specially-prepared, acid-proof paint.

Where the finish is dark, the priming coat may be red lead and linseed oil paint; and where the finish is light, a good priming-coat pigment is made of 29% lead sulphate, 41% lead carbonate, 5% zinc chromate, 10% silica, and 15% asbestine. A good black finishing-coat pigment is made of 55% lamp-black and 45% special French ochre; and a finishing-light-coat pigment can be made of 34% lead sulphate, 41% lead carbonate, 10% silica, and 15% asbestine, with sufficient lamp-black to produce a pearl-gray color. This is light enough to be readily seen and stands better than pure white. The vehicle should be pure linseed oil with the necessary drier. All proportioning of ingredients should be by weight.

Where possible, all steelwork directly over steam-railroad tracks should be protected by concrete rather than by paint. Where this is not practicable, the painting should be done at more frequent intervals than is ordinarily necessary.

The preceding records of the opinions of four engineers who are experts on maintenance and repairs cught to afford the reader sufficient data on the subject to serve all practical purposes. There is some unavoidable repetition involved, and there are some minor differences of opinion, because the economics of maintenance and repairs is far from being an exact science. Again,  the treatment of the  matter  of painting encroaches on the special