Meteorological Observations. 503 
Add p’ to each side of (2.): then 
— 5 aed 3°:\ by (9.35 
(+p =P ($) ve 
or po —bp= = 
a quadratic in p’ .*. p is known, and by (3.) 
z= —pt hci 
Yours very respectfully, 
James CocKLE, 
Middle Temple, Feb. 10, 1843. (B.A. Trin. Coll. Cam.). 
ON THE VARIATION OF GRAVITY IN SHIPS’ CARGOES. 
(From another Correspondent.) 
A communication appeared in the last Number of this Journal 
“« On the effect of the variation of gravity on ships’ cargoes in dif- 
ferent latitudes,” the author of which appears to have forgotten that 
two scales are commonly used in weighing goods, and that the weights 
in both must be equally affected by “ variation of gravity.” 
A ton of any kind of goods weighed at the King’s beam in Lon- 
don, and shipped for Madras, will on arriving there counterpoise a 
standard ton weight as it did before shipment, unless an addition or 
subtraction of weight has taken place during the voyage. K. K. 
METEOROLOGICAL OBSERVATIONS FOR APRIL 1843. 
Chiswick.—April 1. Rain. 2. Cloudy: clear and fine. 3. Slight rain: clear. 
4, Rain: cloudy and windy. 5. Fine. 6. Overcast: slight rain. 7. Rain: 
clear and fine. 8. Clear and fine. 9. Easterly haze. 10. Clear and fine. 
11. Frosty: clear and dry: frosty at night. 12, Sharp frost: clear: cloudy: 
clear and frosty at night. 13. Cloudy: frosty atnight. 14. Uniformly overcast. 
15. Hazy. 16. Hazy: fine. 17,18. Light haze: dry air: clear and fine. 
19. Dry easterly haze. 20, 21. Very fine. 22, Showery. 23, 24. Cloudy and 
fine. 25. Rain: clear. 26. Cold rain: very fine: rain at night. 27. Cloudy 
and fine. 28. Slight rain. 29, 30. Cloudy and fine.—Mean temperature of the 
month 0°36 above the average. 
Boston.— April 1. Rain: rain early a.m. 2. Rain: rain early a.M.: rain P.M. 
3. Cloudy. 4. Cloudy: rain early am.: stormy with rain r.m. 5. Windy. 
6. Cloudy: rain a.m. 7. Cloudy. 8. Fine: rain e.m. 9. Cloudy. 10. Fine: 
snow a.M.: snowr.M. 11—13. Fine. 14, Windy: rainearly a.m. 15, 16. 
Cloudy. 17—21. Fine. 22. Cloudy: rain early a... 23. Fine: rain early a.m. 
94, Fine. 25. Cloudy. 26. Fine: rainr.m. 27. Fine: raina.m. 28. Windy. 
29. Fine: rain a.m. 30, Cloudy. 
Sandwick Manse, Orkney.—April 1. Damp: fog. 2. Bright: damp. 3. Bright : 
fog. 4. Cloudy. 5. Damp: drizzle. 6. Rain: clear: aurora, 7. Cloudy: rain. 
8. Cloudy : snow-showers. 9. Snow-showers: hail-showers. 10, Snow-drift : 
showers. 11. Snow-showers. 12. Snowing: drift. 13, Snow-showers: snow- 
ing. 14. Bright: cloudy, 15. Cloudy. 16. Clear, 17. Clear: cloudy. 18, 
Cloudy: damp. 19. Cloudy. 20. Damp: cloudy. 21. Damp: fog. 22. Damp: 
rain. 22. Damp. 24. Bright: cloudy. 25, 26. Rain. 27. Bright: cloudy. 
28. Rain. 29. Fog: cloudy. 30. Fog: bright : fine. 
Applegarth Manse, Dumfries-shire—April 1,2. Heavy rain, 3. Fair and fine. 
4. Rain. 5. Fair and fine: aurora. 6,7. Rain, 8. Rain: thunder: hail. 
9. Fair: frost. 10,11. Hail: frost. 12, Frost a.m.: snow: rain. 13, Frost. 
14—16. Fair and temperate. 17. Fair and temperate: fine spring day. 18— 
20, Fair and temperate. 21. Fair and temperate: showers. 22. Rain nearly 
all day. 23, Raina.m. 24, Rain carly: very fineday, 25. Heavy rain: flood. 
2, Fair. 27. Fair: hoar-frost, 28, Heavy rain. 29. Fairand fine. 30. Fair. 
