TRANSACTIONS OF THE SECTIONS. 
151 
On Fisher’s Venetian Screw Propeller. By J. Grantham, C.E. 
The object of this propeller is to prevent the retardation which occurs in an 
ordinary screw propeller, bv the tendency to produce a vacuum at the ac o 
W* of tlie propeller. To effect this, Mr. Fisher makes si its in the blades to alio v 
'■h water to pass through, and thus to supply the place of the fluid which is 
toward as the screw turns round. These slits give the propeller somewhat the 
ifprtrance of a Venetian blind, and hence its name. Mr. Grantham Bald the pro- 
I'disT had been tried in the Birkenhead Docks with good effect. 
Mr. Jon\ Grantham described his plan for a high-level railway for the Livcrpoo 
“ DC ^. A model on an extensive scale of the proposed railway was placed in the 
l,r - u Hall, and was one of the objects of attraction during the meeting of the Asso- 
'-iViii. The railway is proposed to he placed on the east side of the whole me of 
It is to consist of iron framework, supporting two platforms,—the lower, 
v: ' four lines of rails, to be about 52 feet, wide and 20 feet above the present 
entirely for goods; and an upper platform, with two lines of rails, exclusively 
' Hunger*. As the present length of the Liverpool Docks is four miles, and 
10 »short time be extended to five miles, the necessity of some improved means 
convey^,.,; a | ong the docks ig becoming more and more urgent, and the facilities 
-<h such a railway would present for the shipment of goods without the risk of 
, "7thev are now exposed was strongly enforced by Mr. Grantham. It 
‘ ■ J 1 "?* Hint the railway should be ultimately placed in connexion with the other 
^ Liverpool* bo that goods may be conveyed direct to the docks without 
^ cj reloaded. The cost of such a railway is estimated at .£.’250,000 a mile, and 
*" rorr i passenger traffic alone, it is calculated, would be amply reraune- 
fcjjjl * whlbt . the quay space gained by the platforms of the railway would be 
> c qual m value to the whole outlay. 
■rn, 'S&& adjusted compass, supported by vulcanized india-rubber springs, 
{ «nibited by Mr. Guay ; the object of which was to prevent the action of the 
ei "g influenced by the motion of the ship. 
11 Strength of Iron after repeated Meltings. By William Hawkes. 
[In a letter to the Assistant General Secretary .] 
„ East Foundry, Birmingham, 
l«m c Up S,R ’ Sept. 23, 1854. 
trnvgtl) _» T ou an account, of some experiments that I have had made upon the 
'U*\, ” ;‘ ron a s derived from repeated meltings. I did not commence upon 
ha* HQ. 6 ? 1 ? 1,11 a ( ter the Hull Report of the 23rd Meeting was in my hands. 
Nil i r< , rae time enough to complete the experiments upon the Hot-blast 
The £;j^ 0rb y ns Hall iron. F F 
rr Sht. j j as l ? e Ited in an ordinary pot furnace, the pot holding about 70 lbs. 
niid there? 8 ' VRn onl y the strength of the stronger of the two bars which 1 had 
taken onlvtt ,n niakin 5 the comparison with Mr. Fairbairn’s experiments I 
of a.• ae strongest of the three bars. I have in each case tested the 
° 0 ''lor... w -.,h fk°V?. tlle P >I5 b Y having it filed down to l inch square, which was 
*hu Corbtft h E Slmton iron. 
P**' uielting h un a * k near Dudley, No. 1 (pig), was more of the No. 2 quality, but 
***** became wh'* 't as . n °t until the thirteenth melting that the outside of the 
‘ 1 '.* l ght pmt kj . j . e » the interior heing light grey, and in the fourteenth melting 
•i'r lameter i n th e * Gav * n lf a grey core of about three-quarters of an inch 
l n -. c ,f l|, teenUi m .i«I , , Indeed it assumed very much the appearance of the bar 
* iron Waa „ B °f the Eglinton iron, exhibited at Hull last year. The Cor¬ 
eas quite fluid at the twenty-ninth melting. 
