WITH NOTES o:n' their fish. 1 1 5 



Ditch," pours into the Bulborne above the upper mill as foul a 

 current of mephitic abomination as ever defiled a watercourse. 



At Berkhampstead the course of the Bulborne becomes incorpo- 

 rated, for the first time, in that of the Grand Junction Canal. The 

 upper and lower mills on this river are mentioned by Chauncy as 

 being, in the year 1271, of the annual value of £6 13s. 4(1. each, 

 and are probably about as ancient as any existing in the district. 



Prom Berkhampstead the Bulborne wends its way along the 

 meadows of a beautiful valley, and, passing Bourne End — where it 

 receives the intermittent outpour of the Hertfordshire Bourne, so 

 well described by Mr. Evans in a paper read about two years ago 

 before the members of this Society*-' — it crosses Boxmoor, and 

 eventually joins the Gade above the paper mill at Two Waters. 



And now a few words about the Gade. As far as I have been 

 able to ascertain by a careful reference to sundiy old maps, the 

 source of the Gade has varied but very little for several centuries. 

 ^Neither railway nor canal has ever yet intruded upon its secluded 

 haunts, or ventured to interfere with the quiet operations of 

 Nature. As the name implies, it rises in the parish of Great 

 Gaddesden, in ordinary years at a point not far distant from the 

 church, but in wet seasons it occasionally makes its appearance 

 considerably higher in the valley. In the month of February, 

 1877, a strong spring burst out from the side of the hill near the 

 Lambsey homestead, and flooded the Dagnall road for nearly a 

 mile. 



The head of the Gade is about five miles distant from the source 

 of that branch of the Ouzel which rises near Totternhoe, and 

 about four miles from that of the Bulborne at Dudswell. After 

 leaving Great Gaddesden and passing the picturesque hamlet of 

 Water End, the Gade pursues its course along the valley of Hemel 

 Hempstead by Marlowes to Two Waters. At Two Waters it more 

 than doubles its volume by a confluence with the Bulborne, and, 

 passing onwards by Kash Mills, King's Langiey, Hunton Bridge, 

 Cassiobury Park, and Croxley Hall, falls into the Colne a little 

 above Eickmansworth. Mr. Evans considers that the valleys of 

 the Bulborne and the Gade were both mapped out in a pre-glncial 

 period, but it is probable that the gap in the Chalk hills at Dagnall, 

 and the depression in the same formation at Park Hill, near the 

 Tring railway station, are due, at any rate, in some degree to the 

 chemical dissolution and abstraction of the chalk by the four rivers 

 which take their rise in the two localities. 



In order to demonstrate that this process is still in active opera- 

 tion, I have attempted to gauge the quantity of water which 

 passes down the Gade at Hunton Bridge, and I think that it cannot 

 avei'age less than 30,000 gallons per minute. Professor Attficld, 

 who has kindly assisted me by analysing a portion of this water, 

 and also by sending me an analysis of some water taken from a 

 well which is sunk in the neighbouring chalk, informs me that 



* 'Transactions,' Vol. I, p. 13". 



