452 The Tropical Tempest Simpiesometer. [No. 138. 



worst character which an instrument can get becomes (and really is) 

 attached to it, L e. that it is " very liable to get out of order." The Duke of 

 York's Simpiesometer is still in Calcutta, but gives indications differing 

 half an inch from the Barometer, as I have heard : one sent to me for trial 

 gave regularly on an average 0.7 above the Barometer standard, and at 

 28.5 or 27.00 inches of pressure, with temperature 80°, would have been I 

 think useless, or the gas would perhaps have escaped ; hence, as I judge the 

 universal complaints against Simpiesometers which have been long in use 

 in tropical countries. 



The remedy for this last defect is also simple enough, and if Messrs. 



will try it, I shall be glad to assist them in making the improvement 

 known in India, and especially in Calcutta. It consists in making the scale 

 and tube long enough to leave at least half of an inch column of oil at 

 pressure 26.00 and temp. 84°, and as I have said before, keeping the Sim- 

 piesometer in the dark. I think these improvements would give, if not a 

 title to a patent, at least to a new name, " Tropical Tempest Simpie- 

 someters." 



P. S. — I have seen in some patent Simpiesometers a contrivance for cork- 

 ing the cistern when moving the instrument. If instead of a cork this 

 was a stopper of caoutchouc, and could be screwed down, it would be a great 

 improvement. 



Messrs. Troughton's note to Mr. Lepage is as follows : — 

 R. C. Lepage, Esq. 



29^ December, 1842. Fleet Street. 

 Sir, — I find that in extreme cases, such as those mentioned by Mr. Pid- 

 dington, the Simpiesometer would get beyond the range of the scale, and 

 suffer the damage described in his letter ; moreover, I think that a door to 

 the case in order that light may be admitted only when necessary, a very 

 judicious precaution. 



If you desire it, we can soon prepare one with the improvements. 



I am, &c. 



(Signed) W. Simms. 



The instrument has just been landed, at a cost of sixty-four rupees, and a 

 brief description of it may be worth putting on record for our distant sub- 

 scribers. The tube is, from top to the bottom of the curve, 18 inches 

 long, the common Simpiesometers being only about 15, and at a pres- 

 sure of 26 inches, with a temperature of 80°, would still leave about an 

 inch of oil above the level of that in the cistern : and 1 trust it is not likely 

 to undergo any severer trial. There is a slide with (I suppose,) a caoutchouc 

 stopper to the cistern, and the usual register plates at the bottom. 



