The use of the series-multiple connection is a distinct step forward in dry-cell use. The arrangement of cells shown in Figs. _C_ or _D_ is better than the arrangement in Fig. _A_, in just the same way that a team of horses is better than a single horse. One horse pulling a load of 2 tons may become exhausted in one hour, but two horses pulling that same load may work continuously for six hours. It is true that in Fig. _C_ there are twice as many cells used as in Fig. _A_, but the eight cells in Fig. _C_ will do from three to four times as much work as the four cells in Fig. _A_. In other words, while more cells are used in the multiple-series arrangement, the amount of service per cell is greater and the service is, therefore, cheaper in the multiple-series arrangement. Some battery manufacturers sell their batteries put up in boxes, the cells being connected up in multiple-series and surrounded by pitch or tar to keep out the moisture. This has certain advantages as well as certain disadvantages. One of the objections to this method of putting up dry cells is that if by any chance one cell out of the eight or twelve which are buried in the pitch is defective it will run all of the cells down, and being buried offers no means of detection or removal. It is not possible to guarantee absolutely that a weak cell will not be occasionally included in a large number, so dry cells may be expected to vary to some degree among themselves. It is interesting to know the effect of one weak cell on a series-multiple arrangement. If, for example, in Fig. _C_ or Fig. _D_, the dotted line connecting (_a_) and (_b_) be used to indicate a cell which is partly short-circuited by internal weakness or external defect the result is as follows: In the arrangement shown in Fig. _C_, where one cell of the upper four is short-circuited, the lower four will discharge through the upper four even though the external circuit is not closed; that is, one short-circuited cell will cause a run-down in all of the cells. In Fig. _D_, however, one short-circuited cell will influence not the entire set but the other one to which it is directly connected. There is thus seen to be an advantage in the arrangement of Fig. _D_ and Fig. _E_, over the arrangement in Fig. _C_.