so as to run magnetically east and west, beginning at the east end and supposing that the surveyor did not come across any areas of local

FIG. 7. Secular variation in the position of the agonic curve of North America between A. D. 1700 and 1900, according to C. A. Schott.

attraction, the boundary as mapped out by the compass would be the line indicated on the map (Plate XVII). It will be seen that

Emmitsburg and Edgemont would be in Pennsylvania and Hancock on the boundary. The maximum deviation from Mason's and Dixon's line-about 2 miles-would have occurred near Leitersburg and the west end of the line would be too far south by nearly a mile.

If now a magnetically east and west line were re-run at the present time, starting again from the east end, the line, as will be seen, would run considerably south of the true boundary. The rich coal regions of Allegany and Garrett counties would now lie almost entirely in Pennsylvania and the west end of the line would be just about at the middle point of the west boundary line, or in other words about 19 miles too far south!

This illustration brings the fact of the secular change of the magnetic meridians in the course of one century vividly before the mind. Fortunately, the Mason and Dixon line was run true east and west, and hence will be fixed forever.

Now let us suppose that a surveyor were called upon at the present time to re-run the magnetic east and west line of 1800. Then the question of proper allowance of secular variation would enter in and be the dominating factor in the accurate re-running of the line. Making the most favorable supposition possible, the precise position of the 1800 magnetic east and west line would never again be regained. Under favorable suppositions a skillful surveyor might approximate quite closely to the line, but assuming that conditions exist similar to those prevailing in the greater portion of the state, even the skillful surveyor might run a line which would be so far out as to make it doubtful whether certain towns belonged to this state or the adjoining ones. His line might be a fruitful cause of litigation for ownership of valuable districts, e. g., the coal regions. This is precisely the condition of things in many parts of Maryland to-day, hence the practical importance of making our secular variation data as accurate as possible. During the present year special effort will be made to increase our knowledge of the secular change.

DESCRIPTIONS OF MAGNETIC STATIONS IN

MARYLAND.

STATIONS OCCUPIED BY THE MARYLAND GEOLOGICAL SURVEY IN 1896.

The arrangement of the stations is alphabetical. The number indicates the general order in which the stations were occupied, and at the same time serves as a brief method of designating the various stations. When an additional station was obtained in the same town or locality a capital letter is attached to the number.

All the stations were temporarily marked at the time of observation by wooden stubs with brass nails or screws in their tops. These stubs were left in the ground. No money was available for marking the stations more permanently, nor was it particularly advisable, except in a few cases, to spend any great amount of time or money in this way. The descriptions below will, in general, suffice for future observations at the identical station.

30. ANNAPOLIS, ANNE ARUNDEL COUNTY.-On the Naval Academy grounds, in the open area near the Observatory; 45 paces west-northwest of Observatory and 62 paces northeast of Herndon Monument. Site was chosen by Professor Terry, in charge of the Physical Department of the Academy.

32. BALTIMORE, FORT MCHENRY.-The description furnished by the Coast and Geodetic Survey of their station occupied in 1895 by J. B. Baylor, Assistant, is as follows: New station selected is in the large open space in the extreme eastern part of the fort next to the outer sea-wall; 161⁄2 yards from the outer sea-wall and 13 yards from a locust tree, and is marked by a substantial locust post with a copper tack in it, and sunk flush with ground. Site is quite free of artificial disturbing influences, such as pipes, ordnance materials, etc.

The Geological Survey station was placed as near as possible to above station. The locust post could not be found, but with the aid of the orderly who had assisted Mr. Baylor, it was possible to locate within a few feet of Mr. Baylor's station.

[The former C. and G. S. station of 1877 and 1885 in another part of the grounds had to be abandoned on account of proximity of electric cars. The commander of the Fort states that there is a bed of iron below the grounds of the Fort.]

29. BEL AIR, HARFORD COUNTY.—In the garden back of Rouse House, a hotel; 110 paces back of the house, 41 paces north of south barbed-wire

fence and 34 paces west of east fence at a point where stands a small willow tree. Site appears to be free from any artificial disturbing influence.

[The above hotel is now known as Eagle Hotel.]

33. BELCAMP, HARFORD COUNTY. On the farm belonging to Mr. James Walsh and occupied at present by Mr. E. J. Cottle, about 400 feet back of railroad station, 34 paces west of first locust tree, 25 paces south of wild cherry tree and 29 paces west of hay crib blown down by storm.

13. BERLIN, WORCESTER COUNTY.-In the northwest corner of Buckingham High School grounds; 61.2 feet from the northwest corner of the frame building and 21.8 feet (at right angles) from the fence in the rear of grounds.

4. BRANDYWINE, PRINCE GEORGE COUNTY.-In the woods about 100 yards east of railroad station. Dip only observed. Soil, sandy.

37. CARDIFF, HARFORD COUNTY.-In the open lot about 100 yards southeast of railroad station; 32 paces from the white wooden fence and 8 paces from fence near road. [In 1897 additional stations were obtained in Cardiff and vicinity. Marked local disturbances were encountered.]

8. CENTREVILLE, QUEEN ANNE COUNTY.-In the grounds of the Centreville Academy for boys, about one eighth of a mile east of court house; 62 feet south of south corner of Academy and 44 feet west of young sycamore tree. Soil, sand and clay.

19. COCKEYSVILLE, BALTIMORE COUNTY.-On Mr. Cockey's property, a large, open lot on right of road near stone bridge. Station is about 500 feet west of road and 25 feet east of a clump of three willow trees.

43. CRISFIELD, SOMERSET COUNTY.-In the large, open lot west of the Academy on 12th and Street; 60 paces from southwest corner of

Academy (a frame building) in a line with rear side of Academy.

35. CRESWELL, HARFORD COUNTY.-About half-way between Creswell and Fountain Green on the road to Belair, about one-sixth of a mile from Winchester crossing, on a small triangular plat opposite Mr. W. H. Michael's place; about four miles from Belair.

23. CUMBERLAND, ALLEGANY COUNTY.-In the large, open area on Camp Hill, north of Rose Hill Cemetery and south of Willis Creek. To find station, go 75 paces along the north iron fence of cemetery, starting from northeast corner, then 75 paces at right angles towards Willis Creek. According to town map, this area is subdivided into lots and streets, but no sign of the latter on the ground at present. Station may have been between Sedgewick and Niagara Streets. According to the map it is about 4667 feet due west of middle point of Decatur Street, on which Mosman's astronomical and magnetic stations of 1864 were located. Station is also about 2744 feet west of court house and about 1280 feet north, and may possibly be over a cement mine. Site was selected in the absence of the County Surveyor by Thomas L. Patterson.

41. DAMASCUS, MONTGOMERY COUNTY.-On Dr. Lansdale's lot, 18 paces from west corner and 42 paces from small house at east corner.

26. DICKERSON, MONTGOMERY COUNTY.-On Mr. Dickerson's farm directly north of railroad depot, in the direction towards Sugarloaf Mountain, near a clump of locust trees about 500 feet from depot. Station is 27 paces west of locust trees and about 18 paces south of wooden fence.

7. EASTON, TALBOT COUNTY.—In the northeast corner of the garden on the east side of Avon Hotel. This station was but a temporary one. Soil, sand and loam. [Local attraction at this place due to iron standpipe; in 1897 the station was selected on the Fair Grounds.]

31. ELLICOTT CITY, HOWARD COUNTY.—In the grounds back of public school up on the hill near the court house and west of old Patapsco Institute; 40 paces back of frame school building near oak tree and 7 paces north of south wooden fence.

27. ELKTON, CECIL COUNTY.-In the south corner of grounds around new high school building just nearing completion; about 49 paces from the nearest edge of building, 13 paces from fence in the rear and 11 paces from fence on the side.

42. FOREST GLEN, MONTGOMERY COUNTY.-On the grass plat under maple tree east of road directly in front of Catholic cemetery.

38. FOREST HILL, HARFORD COUNTY.-In the large, open lot of E. Tucker & Co., west of railroad depot; 200 paces from fence corner nearest the depot and 46 paces east-northeast of cherry tree.

36. FOUNTAIN GREEN, HARFORD COUNTY.-In large open field on Mr. Grant's place; about 200 feet west of store at corner of road and about 25 feet from the middle of the road to Belair; about two miles east of Belair.

34. HARFORD FURNACE, HARFORD COUNTY.-About one-fifth of a mile from the village along the road to Belair; on Mr. A. H. Strausbaugh's farm, 15 paces from the road and opposite "hay bag" on Mrs. Mary D. Walsh's estate.

20. FREDERICK, FREDERICK COUNTY. First Station.-In the southeast part of the grounds back of the State Deaf and Dumb Asylum. Marked by two stakes, one 14x14x8 inches, and another four feet west 2x2x8 inches; the former marks the station and was driven flush with the ground; the station is 26 paces north of the south hedge fence and 34 paces from southeast corner of hedge fence.

20A.

Second Station.-North meridian stone, in the grounds on

the side east of the court house.

[The first station is the preferable one.]

22. HAGERSTOWN, WASHINGTON COUNTY.-In the grounds on the east side of the Hagerstown Academy, down on the slope near the second maple tree on the right-hand side of path to railroad station. The tracks of Western Maryland Railroad are about 300 feet to the west and those of the Cumberland Railroad about 500 feet to the east. Site was chosen by the County Surveyor, Mr. Piper. Marked by an ash stave which broke off when driven. Limestone rocks crop out of the ground.