398 REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMXA CANAL.

1 minute 20 seconds. All are then opened, illing the lock iiia further period of 6 minutes 14 seconds, or 9 minutes 22 seconds in all. These periods are calculated with the coefficient of 0.5 and conform to observations. When no ships are in the lock approaches, all the valves can be opened as soon as the ship')s lines are fast. At least five lines are put out, single parts. The lines are in place and taut by the time the gates are closed. No harm results to ships ascending if all six culverts are opened at once; with descending ships, when no others are waiting, all the culverts may be opened after the first minute or so, when the lines bein to draw across the coping so as to keep taut.
 For the operation of passing f romn one lock to another, the distance to be moved is the length of the lock, which at Patiama will be 1,065 feet. With the same speed as before, the time required from start in one lock to stop in the next will be:

 i Feet. I Minutes. Second,,.!

 To acquire speed of 1.7 mil es per hour moving. 300 4~ 00 To move at rate of 1.7 miles per hour ................ 565 3 4
 To reduce speed to a stop in ........................ 200 2 40
 Total...................................-----1, 065 10 i 26

 Taking into consideration the effect on waiting ships of opening the culverts as observed at the St. Marys Falls Canal and the relative cross-sectional areas of the approach channels, about. 2,750 square feet at the St. Marys Falls Canal and about 1,500 at the Panamta Canal, there is no reason why a much larger culvert area could not be used at the latter canal than at the former. But assuming' it to average only 250 square feet during the process of filling or emptying, taking' a coefficient of 0.6 for cases,- where the water is drawn into a culvert for the length of a lock chamber and discharged through another' of equal length, and a. coefficient of 0.7 for closes where the water passes in culvert only half the distance, the time required for filling or emptying becomes, for a lift of 281 feet (the lift at each of the Gatun locks for the 85-foot level)Mmi. See.
 For filling upper lock or emptying lower lock-------------------------- -------------- 13 27
 For emptying upper lock or filling lower lock-----------------------------------------1I1 06
 The foregoing embraces all the elements for a calculation of what mlay, be called the theoretical capacity of the canal. When a ship has passed from the upper to the lower lock and the middle gates are closed behind it, the upper lock will be filling while the lower' lock is emptying, and as the ship is passing out of the lower lock into the next level the following ship will be entering the upper lock. The cycle may be taken as beginning and ending with the successive openings of the upper gates, and will be as follows: Mmi. See.
 Ship moving from stop into upper lock ------------------------------------------------ 740
 Closing upper gates---------------------------------------------------------------------- 2 00
 Emptying upper lock --------------------------------------------------------------- 11 06
 Opening middle gates------------------------------------------------------------------- 2 00
 Ship moving into lower lock ------------------------------------ -------------------- 10 26
 Closing m iddle gates - - - - - - - - - - - - - - - - 2 00
 Filling upper lock ----------------------------------------------------------------143 27
 Opening upper gates --------------------------------------------------------------- 2 00
 Interval between ships------------------------------------------------------- 50 39

 With this interval the yearly capacity of the two lights would be 3-6-X94X-60 X-2 0.5 oc kages. 50. 65
 The number of lockages above given could not be realized in actual pi-)actice. The HURitle.' of ships arriving' per day would not be uniform. On some days there would not he enough ships to require the continuous operation of the locks, while on other days V ships in considerable number might be awaiting lockage. As the traffic increases the loss of time to ships wil increase in more rapid ratio. At the St. Marys Falls Canal the average time required for passing through