96 Professor Moll on Mr Blanken's Fan-Gate Sluices. 



sions, have been constructed on the same principle since that 

 period, all of which have been found perfectly to answer. In* 

 this country, it has always been held a desideratum to find 

 the means of opening locks against a powerful head of water; 

 this, I think, Mr Blanken accomplished successfully ; I, there- 

 fore, deemed a description of these sluices worthy of being in- 

 serted in your Journal. 



The properties of Mr Blanken's sluices, or locks, are the 

 following : 



1st, That the flood-gates, destined to act against the pres- 

 sure of exterior high water, will, if required, equally act 

 against the interior when it is expedient to sustain it at a higher 

 level than the exterior water. 



2d, That, when the tide or current runs with great force, 

 either in or out of the locks, the gates may be easily, safely, 

 and speedily shut, whatever be the direction of the current. 



3d, That the gates can be opened with ease, even when a 

 head of seven or eight feet of water bears upon them. 



The annexed drawing in Plate IV. is of a sluice of this de- 

 scription. It was built in 1818, near the town of Gorinchem, 

 in Holland. It opens a communication between the river Linge 

 and the newly made canal of Steenenhock, and it is alike des- 

 tined for the purpose of inland navigation, and of evacuating 

 or retaining superabundant water. Whenever the waters of 

 the Linge are swoln by a rise of the Rhine, it becomes dan- 

 gerous to admit them into the canal ; but, at the same time, 

 it is required that the locks can be opened at pleasure, what- 

 ever be the difference of levels in the river and the canal. 



Figure 1st of Plate IV. shows a section of this sluice, the 

 second the plan, the third a front view, and the fourth the 

 back part of the sluice, the whole on a scale of 2 ^ 5 of the 

 real dimensions. 



A B are flood-gates, constructed on the ordinary principle, 

 the angle which the gates form being opposed to the river 

 Linge. 



C D and E G are the Jan-gates, thus called by Mr Blan- 

 ken, from some analogy in their form to that of a lady^ fan. 



The gates, C D E, turn on one common axis, D H, Fig. 1. 

 so that, when the gates are shut, D C is in the position shown 



11 



