78. Observed also by Thomas at Pekin.

79. Very roughly observed; visible to the naked eye.

81. Discovered by J. D. Cassini, Nov. 29.

83. Afterwards seen in Europe, with a faint tail 1° long.

84. Scarcely perceptible to the naked eye. The orbit is a hyperbolic one, and remarkable for its enormous perihelion distance, the greatest known.

86. Elements only approximate.

88. Visible to the naked eye, with a tail 6° or 8° long.

89. Very imperfectly observed. An elliptic orbit; period assigned, 5'436 years. 90. Very uncertain. Visible to the naked eye.

91. The finest comet of the 18th century. On Feb. 15 it had a bifid tail, the eastern portion being 7° long, and the western 24°. Visible in a telescope in the daytime. Euler has calculated an elliptic orbit, to which he assigns a period of 122,683 years!! The statement of this comet having had six tails is believed to be a fabrication.

92. Elements uncertain, but they strongly resemble those of the comet of 1231. It passed very near the Earth.

93. Observed only during 1746.

94. Discovered by J. D. Maraldi, April 30. Visible to the naked eye, with a tail 2° long.

95. Very uncertain.

96. Elements tolerably reliable. It had a small tail.

98. The first predicted apparition of Halley's comet. On May 5 its tail was 47° long.

99. Visible to the naked eye, with a tail 5° long.

comet of 1449.

Elements resemble those of the

100. This comet came near the Earth, and moved with great rapidity; it had a tail 4° long.

IOI. It had a small tail.

102. An elliptic orbit; period assigned, 7334 years. Lexell makes it 1137 years.

103. Visible to the naked eye, with a tail 2° long.

105. Discovered by Messier, April 8. An elliptic orbit; period assigned, 5'025 years. Visible to the naked eye, with a tail 3° or 4° long.

106. Visible to the naked eye, with a tail from 60° to 80° long. Bessel assigns 2090 years as the most likely period of revolution. He has shewn that an error of 5" either may increase the period to 2673 years or diminish it to 1692 years.

107. The celebrated Lexell's comet. The diameter of the head, July 1, was 2. It had also a small tail, and approached within 1,400,000 miles of the Earth. 108. It had a faint tail, 5° long.

109. The orbit of this comet is undoubtedly hyperbolic. It had a tail about 2° long.

110. The first recorded apparition of Biela's comet.

111. Just perceptible to the naked eye.

113. Discovered by Messier, Jan. 18.

114. An elliptic orbit; period assigned, 75,314 years.

115. Discovered by Olbers on the same day.

116. Visible to the naked eye, Nov. 9, with a tail 3° long. It came very near the Earth.

118. An elliptic orbit; period assigned, 5.613 years.

119. Visible to the naked eye, with a tail 2° long.

120. Not only are the elements uncertain, but it is doubtful whether the comet ever existed.

122. Visible to the naked eye, with a tail 8° long. 123. The first recorded apparition of Encke's comet. 126. Visible to the naked eye, with a tail 24 long.

128. Imperfectly observed on four occasions. Elements only approximate.

134. Discovered by Miss Herschel, Oct. 7. An elliptic orbit; period assigned, 422 years.

135. An apparition of Encke's comet. It was just visible to the naked eye. 136. Very faint.

137. Discovered by Miss Herschel and Lee on the same evening; by Rüdiger, Aug. 15, and by Kecht, Aug. 16.

139. Discovered by Olbers, Dec. 18. Elements only approximate.