CXVIII, A. B. PORTUS. 
about £8,000 of this amount was paid for the “Von Schmidt” 
pump and machinery and the right to use it. Mr. George 
Higgins having secured the patent for Australasia, contracted 
with Mort’s Dock Co. to fit it to the “Groper.” Although the 
vessel has been working about three years no favourable oppor- 
tunity has arisen for testing the machinery at its best effort as 
far as cost per ton is concerned, because instead of working 
steadily at original soil the material dealt with has been inter- 
mittently dumped alongside, the cost of pumping on shore vary- 
ing, according to distance, from 13d. to 24d. per ton, the cost 
under the old system of barrows and shovels would, for very 
short distances, have been from 6d. to to 1s. 2d., while for from 
one-third to half a mile the price would have been prohibitive. 
So much useful work having been done by the suction dredges _ 
of the Harbours and Rivers Department at Sydney, N ewcastle, 
and the northern rivers (see schedule attached) the present 
Minister for Works, Mr. Young, determined to convert a number 
of grab dredges into small sand pumps. (Plates 6 and 9.) Three 
of them have been so altered, and three others are in course of 
alteration. The hulls of iron, were cut and lengthened at the 
Fitzroy Dock works, and special engines, boilers, and centrifugal 
pumps fitted ; the Priestman cranes were retained on board ; the 
jib being availed of for carrying the suction pipe which passes 
’ through the bow of the vessel and being fitted with a gimbal 
joint, the end of the pipe has a considerable range of action, 
enabling the dredge to cut its way through sand banks uncovered 
at high tide. If clay or other material unsuited for the Dutch 
pump is met with, the suction pipe is quickly removed anda grab 
bucket being attached to the jib chain the Dual machine becomes 
an ordinary grab dredge. In practice, however, it is found that 
_ On our rivers the alteration from pump to grab is seldom necessary; 
the obstructions to navigation consisting almost wholly of material 
easily dealt with by a suction dredge. The pump engines in the — 
largest of these combined machines indicate aboyt 180 H.P., the 
__ cylinders are 12” and 24”, supplied with steam at 120 Ibs. pressure 
