care, the rule being that for the piece considered the length of span to be used in applying the live-load diagram is the total length of structure which must be covered by the moving load in order to obtain the greatest stress in the said piece, excepting only the suspended span and the main central span, for which the live loads actually imposed are to be treated exactly like those of simple spans. Of course, the impact is to he figured for the length of structure that must be covered by the live load to produce the greatest stress in the piece under consideration.

Some young engineers have an idea that the finding of stresses in cantilever bridges is a complicated matter. On the contrary, it is very simple, as every stress can be determined by the ordinary principles of statics and very readily by the use of graphics. Although the work is simple, it is somewhat long and tedious, as is evident from the preceding lists of stresses. The computer is advised, when finding the stresses, not to try to group the loadings any more than they are grouped in the said lists, for, if he does, he will probably have to separate them while making his combinations.

In respect to combinations of stresses during erection, there will be no necessity for increasing the sections proportioned for other combinations, provided they are as large as those required by the said erection-stress combinations with the intensities given in the specifications (Chapter XIV.) for combinations that include wind-stresses, viz., intensities thirty per cent higher than those for combinations without wind stresses.

Cantilever bridges may be made either through, deck, or half-through; but a combination of deck-spans for the anchor-arms and a through-span for the cantilever-arms and suspended span is awkward-looking and unsightly. There is a structure of this type across the St. Lawrence River, near Montreal.

It is no easy matter to give an artistic effect to a cantilever bridge; nevertheless it is generally within the realms of possibility to do so, although it must be confessed that most of  the  existing  structures of this type are uncompromisingly