Calculation of Heights, determined by Barometrical Measurement. 85 
If, on the contrary, we prepare this colt’s foot with due allowance for the supe- 
rior rapidity of growth of horn at the toe, if we put it in such a shape as will bring 
the foot to’ the natural position by the end of the second week ; we shall have had, 
for the first and second week an irregularity on one side gradually correcting it- 
self; we shall then have a perfect position of the foot ; and during the third and 
fourth weeks, we shall have an irregularity on the dangerous side, only so great 
however as what would have taken place, at so early a period as the end of the second 
week, under the other system of management. If the existence of thatdue propor- 
tion between the masses of horn, in the different parts of the hoof, for which I con- 
tend, is destroyed by the existence of too small a quantity in the forepart of the fopt, 
during the first fortnight, the evil consequences to he dreaded therefrom will be 
counteracted during the fortnight ensuing, and an equilibrium will thus in a man- 
ner be maintained. . 
But as every forced change, in the position of the foot, from that for which 
nature adapted the various joints and tendons, must he an evil dangerous in 
proportion to its extent; it will appear, that the greater the frequency with 
which the foot is brought into its natural position, and the oftenerthe equilibrium 
of the masses of, horn is restored, the fewer will be. the chances of injury, either to 
the joints, or the form of the hoof. In place then, of a change of shoes every 
month, as assumed above for illustration's sake, let us suppose them to be shifted 
every fortnight ; and the hoof being trimmed each time, with reference to the 
change of form, from the unequal growth of horn, which the hoof must undergo 
during the interval, always aiming at having the foot in its proper shape and 
position during the middle of the term ; and we make as near an approach to what 
appears, in theory at least, perfection in shoeing, as can he obtained ; because by 
so doing we keep the relations of the different parts of the hoof more nearly in 
their natural state, and the extremity of the limb more nearly in its natural posi- 
tion, than we can do by any other mode of treatment. 
The above are crude thoughts and conclusions, grounded upon what appear to be 
true and obvious principles- They are offered, not as the result of well conducted 
experiments, made with reference to the determination of the truth of the views 
submitted; but because the hecessity for keeping the masses of horn in some sort 
of equilibrium docs not appear to have occurred to any of those writers who have 
treated the subject scientifically, as being a desideratum in the treatment of the 
horse's hoof, and because it is still unfortunately found, that the majority of hoofs, 
after being in the hands of the farrier, do lose their natural shape, however smoothly 
they may be pared out aud trimmed, with whatever skill the semblance of na- 
tural bars along the sole may be created by tbe dexterous use of the drawing knife, 
and with whatever art the heels may be made to assume the appearance of that 
width, which nature intended they should in reality possess. 
lll.—Onthe Calculation of Heights, determined by Barometrical Mea- 
surement. 
To the Editor of Gleanings in Science. 
Sir, 
The method of measuring tbe heights of mountains by the barometer is well 
known. The formula generally employed when a book ofl ogarithms is at hand is 
sufficiently short, and (to those acquainted with the principles on which it is 
founded) simple. Nevertheless I have found that to some it appears perplexing ; 
add to which, a table of logarithms may not be immediately procurable in many 
cases. At all events I have thought that a simple method of deducing the results 
of barometric measurements, which, besides being independent of logarithms, 
should be entirely free from ambiguity, might prove acceptable to some of your 
readers. If you are of this opinion, you will oblige me by giving insertion to this 
communication in one of your early numbers. 
I am, 
Sir, 
Yours obediently, 
D, 
