=Procedure with Unequal Zones or Irregular Lots.=--Where the zones are not equal in area or the property lines do not intersect the roadway at right angles or the lots are irregular in shape, the method of procedure is not quite so simple, although the principle is the same. While it is customary to make the zones of uniform width this is not absolutely necessary. Likewise the ratio of weights vary with different states and cities. One city uses 33¹⁄₃, 20, 16²⁄₃, 10, 10, 10 for the weights in its six zones; another uses 33¹⁄₃, 25, 16²⁄₃, 15 and 10. Neither of these, as shown in the tables on pages 315 and 316 varies materially from the theoretical ratio. Using the latter of these ratios a small district has been worked out as shown in the figure and table on page 320. Incidentally this also shows a good method of recording lot assessments during the process of computations. The work is readily checked. The sum of the lot areas must equal the sum of the zone areas and that of the whole district. The sums of the weighted areas for the same divisions must balance. The sums of front-feet likewise. Also cross and vertical summations may be made to check. [Illustration] =Second Method of Apportioning Assessments.=--A second method based upon a different definition has something in its favor. If the front-foot is defined as a lot 1 foot wide measured in the direction of the street extending directly back through all the zones to the limit of the assessed area it will have a weighed area of _W__{1}_z__{1} + _W__{2}_z__{2} + _W__{3}_z__{3} ... and so on, where _W__{1} represents the weight of the zone, whose width is _z__{1}, and _W__{2} the weight of the zone, width _z__{2}, etc. If _z__{1} = _z__{2} = _z__{3} ... etc., as is usually the case the weighted area of 1 front-foot is (_W__{1} + _W__{2} + _W__{3} ... ) _z_ = _Wz_ = 100_z_, since _W_ is always = 100. The total number of front-feet in the district, or in any lot, will be the number of weighted feet in the district or in the lot, divided by 100_z_. In the district represented on p. 320, the number of front-feet is the total frontage, 1,936,000 divided by 4000 = 484; and for each lot the amount shown in the table. The results obtained by the two methods are directly proportional, so that either may be used for making assessments. In fact they are proportional to the weighted areas, so that the weighted areas may be used instead of the front-feet if desired. =Rule for Assessment.=--To get the assessment for any particular lot divide the total cost of the improvement by the total number of front-feet in the district and multiply the quotient by the number of front-feet in the lot. [Illustration: