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Mechanics. — Effects of Salt upon Celery. 



Vol. VII. 



that it might become thickened and scirr- 

 hous, so as to make the cow liable to inflam- 

 mations, and probably loss of some of the 

 quarters. Samuel D. Martin. 



Colbyville, Kentucky, April 3d, JS43. 



Mechanics. 



Why are wheels generally made of a 

 dished form — that is, inclining- outwards? 



Because they thus acquire astonishing- 

 strength, indeed that of the arch, as con- 

 trasted with the flat or upright wheel ; the 

 dished form is further useful in this, that 

 when the carriage is on an inclined road, 

 and more of the weight consequently falls 

 upon the wheel of the lower side, the infe- 

 rior spokes of the wheels become nearly 

 perpendicular, and therefore support the in- 

 creased weight more safely. The disadvan- 

 tage of these wheels, however, is, the in- 

 clining wheel naturally describing a curved 

 pith, the horses, in drawing straight forward, 

 have to overcome this deviating tendency in 

 all the wheels. 



Why are the fore-wheels of carriages 

 smaller than the hind-wheels'? 



Because they facilitate the turning of the 

 carnage. The advantage of the wheel is 

 proportioned to the magnitude ; the smaller 

 wheel having to raise a steeper curve. It 

 is not true, however, according to the popu- 

 lar prejudice, that the large hind-wheels of 

 coaches and wagons help to push on the 

 little wheels before them. 



From these causes, continues the same 

 ingenious writer, "the difference in perform- 

 ing the same journey of a mile, by a sledge 

 and a wheel-carriage is, that the former rubs 

 over every roughness in the road, and is 

 jolted by every irregularity; the rubbing 

 part of the latter, the axle, glides very 

 slowly over about 30 yards of a smooth oiled 

 surface, in a gently waving line. It is as 

 certained that the resistance is thus reduced 

 to 1-100 of what it is for a sledge." 



Why do springs not only render carriages 

 more easy vehicles on rough roads, but much 

 lessen the pull to the horses? 



Because where there is no spring, the 

 whole load must rise with every rising of 

 the road, and must sink with every depres- 

 sion, and the depression costs as much as 

 the rising;, because the wheel must be drawn 

 up again from the bottom of it ; but in a 

 spring carriage, moving rapidly along, only 

 the parts below the springs are moved, in 

 correspondence with the irregularities, while 

 all above, by the inertia of the matter, have 

 a sort and steady advance. 



Again, springs of carriages convert all 

 percussion into mere increase of pressure: 



that is to say, the collision of two hard bo- 

 dies is changed by the interposition of one 

 that is elastic, into a mere accession of 

 weight. It is probable, that under certain 

 modifications, springs may be applied with 

 great advantage to the heaviest wagons. 



In surmounting obstacles, a carriage with 

 its load being lifted over, the springs allow 

 the wheels to rise, while the weights sus- 

 pended on them, are scarcely moved from 

 their horizontal level. 



Why are "under-springs" so advantageous 

 in very modern carriages? 



Because they insulate from the effects of 

 the shocks, all the parts, excepting the 

 wheels and axletrees themselves. When 

 only the body of the carriage is on springs, 

 the horses have still to rattle the heavy 

 frame-work below it, over all irregularities. 



Why should a road up a very steep hill, 

 be made to wind or zig-zag all the way? 



Because, to reach a given height, the ease 

 of the pull is greater, exactly as the road is 

 made longer. 



Why is it important to make roads as 

 level as possible ? 



Because, a horse drawing on a road where 

 there is a rise of one foot in twenty, is really 

 lifting one-twentieth of the load, as well as 

 overcoming the friction, and other resistance 

 of the carriage. — Arnolt. 



Effects of Salt upon Celery. — Some 

 time ago, we pointed out the beneficial ef- 

 fects of salt in growing asparagus. There 

 is another plant cultivated in gardens, which 

 would be greatly benefited if a little more 

 salt was added to its food — for I believe the 

 manure which it commonly receives, is as 

 wairish to its taste, as brose without salt to 

 a Scotchman. Celery is the plant I mean; 

 I recollect gathering it in a wild state, some 

 years ago, on the north side of the Frith of 

 Forth, in situations that would be watered 

 by spring tides — and, I believe that it is 

 commonly found, both in England and Scot- 

 land, in ditches near the sea. This season 

 I gave a considerable quantity of salt to a 

 row of celery, by putting it between the 

 plants some time after they were planted. 

 I then watered them freely, which carried 

 the saline particles down to the roots. This 

 appears to have done the plants much good, 

 for they grew remarkably well afterwards. 

 From the Report of the Covent Garden 

 market, some time ago, it appears that 

 celery this season, has been rather shorter 

 than usual. Some of my plants to which 

 salt, was applied, measured, by the middle of 

 September, four feet in height, 30 inched 

 of which were well blanched. — Gardiner's 

 Chronicle. 



