Glengista

According to the Old English Dictionary:

The translator seems to have misunderstood the passage to mean: 'In order that thy diligence and genius may add somewhat to the knowledge of these things of mine.' In some way

glengista

ingenium is represented by glengista. Could this word be the superlative of an adjective, glenge well-ordered, and the passage be completed ?þín] glengista [orþanc?]; cf. glengan; III. glengista