... not by latitude and longitude.
……不是通过经纬度的方法。
Thus position AB1234 would indicate point, say 55 degrees 30 minutes North, 25 degrees 40 minutes West.
比如，AB1234可能代表着北纬55度30分，西经25度40分。
This of course presented no problem to us once a portion of a gridded chart had been captured and the whole reconstructed.
这本身并无问题。
But in (September) 1941 the Germans started transposing these letters, square AB becoming, for example, XY
但是在1941年9月，德国人更换了这套标识，例如将AB换成XY，
while a figure would have to be added to or subtracted from the numerals, so that 1234 would appear in the text of the signal as, say, 2345.
并且对数字进行了一些加减，例如1234在通信中会说成2345。
These transpositions were changed at regular intervals.
这些变换本身，也按照某种规律，周期性地变化。
Yet either the Enigma was being read, in which case these precautions were a feeble response, or it was not, in which case they were a waste of time.
如果说德国已经知道谜机被破解了，那么这些改进措施就显得太幼稚了，如果他们不知道，那么这些措施就是浪费时间。
The rationale lay not in foiling the British cryptanalysts, but in creating a defence against imagined spying and treachery.
但实际上，德国做出这些改变，并不是为了难住英国的密码专家，而是为了防止可能会出现的间谍或叛变。
The cumbersome disguise succeeded in confusing their own officers:
这些麻烦的变换，成功地迷惑了他们自己的官员：
On one occasion we successfully solved a disguised grid reference and diverted a convoy clear of a waiting patrol line,
有一次，我们破解了一个坐标网格，并在巡逻线上执行了一次护航清扫，
only to find that the C.O. of one of the U-boats involved had not been as clever as we had and had misinterpreted the disguised grid reference given in his orders and blundered into the convoy in consequence.
结果只发现了一艘潜艇。这艘潜艇似乎误解了他接到的命令中的坐标，结果撞入了清扫范围。
In November 1941 the system was made even more complicated, and gave rise to long periods of uncertainty at Bletchley.
在1941年11月，这个系统被改得更加复杂，布莱切利陷入了长时间的困惑。
They were still on a knife-edge, and were never allowed to forget it.
他们仍然站在刀尖上，从未忘记这一点。