1842.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



173 



THE NEW TARIFF ON TIMBER, DEALS, &e. 



The important change that is liliely to he eiftcted in the duties on the 

 abore articles has induced us to give the following information relative to 

 the present and the proposed new duties ; liliewise a talile which shows more 

 immediately the differences between the old and new duties on foreign deals. 

 We did not consider that it was necessary to extend the table to deals from 

 British possessions, as the proposed new duties are so very trifling, and can 

 be easily calculated from the cubical contents we have given of the various 

 lengths of planks, deals, and battens in the table. 



Present Duties on Timber and Deals imported into Great Britain 

 FROM Foreign Countries and British Possessions. 



Battens, not exceeding 7 inches wide and 2f in. 

 in i/iici-ness per 120 



„ Ends, under 6 feet long 



„ 6 ft. in length and not exceeding 16 ft. 



„ exceeding 16 ft. and not exceeding 21 ft. 



21ft. „ 45 ft. 



Deals, above 7 inches wide and not -exceeding 



3} in. in thicliness per 120 



" Ends, under G ft. long 



„ 6 ft. in length and not exceeding 16 ft. 

 „ exceeding 16 ft. and uot exceeding 21 ft. 

 21ft. „ 45 ft. 



„ exceeding 45 ft. or above 3^ in. thick, 

 (not being timber 8 in. square and upwards) 

 per load of 50 cubic feet 

 and farther per 120 



Timber, 8 in. square & upwards, per load of 50 c. ft. 

 Wainscot logs ditto 



Oak ditto 



Teak ditto 



Mahogany per ton 



Ditto from Honduras ditto 



Balks, Ufers, and Fir Quarters, under 5 in. square, 

 and under 24 ft. long per 120 



Ditto 24 ft. long and upwards „ 



Lathwood, in pieces under 5 ft. in length, per fathom 

 „ 6 ft. wide and 6 ft. high 

 „ 5 ft. and under 6 ft. 

 8 ft. „ 12 ft. 

 „ 12 ft. and upv\ards 

 Firewood per fathom 



3 



10 



11 10 

 20 



6 



19 



22 



44 



Foreign. British. 



£ s. d. 



2 10 

 6 

 2 15 

 2 15 

 2 15 



10 

 12 

 10 



10 

 4 



1 10 



3 5 



4 17 6 



15 

 1 5 

 10 



Proposed New Duties. 



Table showing the Comp.vrison of the Present Duty and the 

 intended New Duties on Planks, Deals and Battens from 

 Foreign Countries. 



The change in the timber duties will come into operation on the 10th of 

 October, 1842. 



EXPLOSIONS OF STEAM BOILERS. 



The calamitous accident which occurred lately in the Clyde has recalled 

 public attention to this subject, and there can hardly be a doubt that unless 

 means can be devised of rendering explosions less frequent, there will be some 

 legislative enactment upon the subject. We shoiUd desire much to see the 

 causes of explosions investigated at the instance and under the direction of 

 the Steam Association, with the view of inducing the voluntary adoption of 

 measures calculated to avert such disasters. The influence of example and 

 the force of opinion would be productive of far greater amelioration than 

 any legislative interference without giving rise to any of the confusion, irri- 

 tation, and injury which such an interference would create. From a variety 

 of circumstances which have come to our knowledge, we are thoroughly per- 

 suaded that the most prolifio source of explosions is a deficiency of water in 

 the boiler. There can hardly be a doubt that this was the cause of the late 

 explosion of the Telegraph, in the Clyde, as v^■ell as of the Victoria in the 

 Thames, and the Union in the Humber. Explosions generally take place 

 just after the engines have been set to work after having been stopped for 

 some time. In consequence of the inaction of tlie feed-pump wliilst the en- 

 gine is at rest, no water enters the boiler, and the quantity of water left in 

 the boiler is rapidly diminislied by evaporation until the water level falls 

 below the top of the flues. The upper part of the flues consequently becomes 

 red hot, and the rapid generation of steam or the decomposition of the water, 

 immediately that the renewed action of the feed-pump sends a quantity of 

 water upon the red hot plates, induces so great and so sudden a pressure, 

 that explosion immediately ensues. The obvious remedy for this state of 

 things is to furnish every boiler with a contrivance to maintain the level of 

 the water by self-acting means, so that whetlier the engines are at work 01 

 whether they are stationary, the surface of tlie water in the boiler is pre- 

 served at a uniform height without the necessity of any alteration on tlie 

 part of the engineer. It is perfectly possible to accomplish this by a suitable 

 mechanism, and no vessel ought, we conceive, to be without some species of 

 apparatus to attain this end. We have seen one contrivance which is not 

 merely perfectly efficacious, hut extremely simple, and wliicli we would re- 

 commend to tlie notice of tliosc interested in steam navigation. This con- 

 trivance is, we understand, tlie work of Mr. Robert Sinclair, of Gould Square. 

 Tliere may be other mechanisms that we know not of, equally efficacious, and 

 the merits of all should be investigated and the best chosen. But whether 

 viewed as a measure of safety in preventing explosions or fire from an over- 

 heating of the flues, or as a measure of economy in obviating the fearful 

 expense so often arising from boilers being burnt, as is the technical phrase ; 

 we are strongly of opinion that some automatic feeding contrivance ought to 

 be resorted to, and we can speak with much confidence of the merits of that 

 particular contrivance we have alluded to. 



