NATURE 



[Nov. 2, 1 87 1 



confusion ; and in the second, although all parallel planes have 

 the same slope, any number of other planes not parallel can also 

 have it ; the word is therefore not sufficiently definite. " Tilt," 

 a word spoken of by Mr. Proctor, as though it had been suggested, 

 has no geometrical meaning whatever. As a substantive it is a 

 " tent," or " awning ;" it has also been sometimes used poetically 

 as an equivalent to "tournament," and is, I believe, the familiar 

 abbreviation of "tilt-hammer." These are its only meanings, 

 and none of them apply to a plane. 



I would only a(!d that I do not quite see what the fact men- 

 tioned by Mr. Proctor, that he has written twelve books in the 

 last six years — interesting as it may be from a bibliographical 

 point of view — has to do with the matter. 



Oct. 29 J. K. L.\UGHTON 



Three elements are necessary to fix the position of a plane as 

 I understand the word "position." If "aspect ".and "slope" be 

 the names of two of these, the third will be the perpendicular 

 upon the plane from some fixed point. It is because the term 

 " position " implies the fixedness of this third element that it is 

 inappropriate to express my friend Mr. Wilson's meaning. 



My friend Mr. Proctor will pardon me if I do not consider the 

 question entirely settled by the fact that he has written perspi- 

 cuously and explained clearly by the use of a term which fixes 

 too much. With an improved scientific terminology, he will be 

 able to make his next twelve books superior (if that be possible) 

 to those he has written within the last six years. 



"Aspect" and "slope" stand on the same fooling, one con- 

 notes a reference to the points of the compass, the other to the 

 horizon. Neither can be used in Mr. Wilson's sense without 

 departing from their colloquial meaning, but it is perfectly com- 

 petent for geometers to take a word from common conversation 

 and give it a scientific meaning. Either of these words may be 

 used in Mr. Wilson's test sentences. Parallel planes have the 

 same slope, two slopes determine a direction, &c. 



It is yet possible that some correspondent can suggest a better 

 term, either one imported from ordinary life or one conceived 

 for the purpose. 



The Correspo.ndent who suggested " Si-ote" 



Geometry at the Universities 



Prof. Thiselton Dyei; has well pointed out a distinction 

 •which exists between the mathematical courses at Oxford and 

 Cambridge. But his conclusion, that at Oxford " special atten- 

 tion to geometrical methods would pay very well," though ac- 

 ceptable in its way, falls far short of what I advocate. The great 

 want at both Universities is a course of geometrical studies ; and 

 the proof that such a v. ant exists is to be found in the fact that 

 the geometrical treatises in use at either University, cover so very 

 limited a range. Theie are not even any text-books on the 

 geometry of the sphere, cone, cylinder, and like simple solids, 

 or on such curves as the lemniscate, cycloid, and the simpler 

 spirals. A few stray notes on these subjects m.ay be found in 

 some of the text-books, but not a thorough and systematic 

 geometrical investigation of any of them. Geometrical treatises 

 might with advantage range much further. A geometrical treatise 

 on ellipsoids would be of immense use apart from its employment 

 as a means of mental training. Oeometiical treatises on para- 

 boloids of both kinds, on hyperboloids of one sheet and of two 

 sheets, on the various orders of ring-surfaces and screw- surfaces, 

 and on many o!her tiidimensional matters, would afford invaluable 

 exercise to the student, besides having a real value to the scientific 

 worker. I venture to express my conviction, that a course of 

 such studies would tend to develop mathematical powers much 

 more thoroughly even than the study of covariants and contra- 

 variants, Jacobians, Hessians, d /wc gams onine. 



If there is one department of mathematical research in which our 

 countrymen are fitted by their mental habitudes todistinguish them- 

 selves pre eminently, it is precisely this neglected department of 

 geometrical research. As it is, though we have i;eometricians of 

 great power, no systematic geometrical work is done in England. 

 Our treati^es )ange only over the most elementary geometrical 

 subjects, and even in discussing these subjects our writers are 

 fain to accept the assis'ance of Continental geometricians. One 

 would conceive that each of our Universities might yearly send 

 out many who could treat of the elements of geometry without 

 keeping a hand always on some French or German textbook. 



Brighton, Oct. 27 RiCHD. A. Proctor 



DEEP-SEA DREDGING IN THE GULF OF ST 



LA WRENCE 

 T^ H E marine zoology of the deeper parts of the River and 

 -•- Gulf of the .St. Lawrence has not been investigated 

 until quite recently. This suminer, under the auspices of 

 the Natural History Society of Montreal, and in conse- 

 quence of the kindness of the Hon. Peter Mitchell, 

 Minister of Marine and Fisheries for the Dominion (who 

 not only gave me facilities for dredging on board Govern- 

 ment vessels, but also caused sufficient rope to be provided 

 for the purpose), depths of from 50 to 250 fathoms were 

 successfully examined. The greatest depth in the Gulf, 

 to the west of tlie Island of Newfoundland, as given in' 

 the Admiralty charts, is 313 fathoms. It is thought that 

 a general sketch of the results obtained maybe of interest 

 to the readers of N.\ture. 



The cruise lasted five weeks, the first three of which 

 were spent on board the Government schooner La Cana- 

 di'enne, and the remaining two on the Stti/a Maris. The 

 area examined includes an entire circuit round the Island 

 of An'icosti, and extends from Point des Monts (on the 

 north shore of the St. Lawrence) to a spot about half way 

 between the east end of Anticosti and the Bird Rocks. As 

 these investigations were almost necessarily subordinate 

 to the special duties on which the schooners were engaged, 

 in several cases the same ground was gone over twice. 



The bottom at great depths generally consists of 

 a tough clayey mud, the surface of which is occa- 

 sionally dotted widi large stones. So far as 1 could 

 judge, using an ordinary thermometer, the average tem- 

 perature of this mud was aboiit 37° to 38^ Fahrenheit, at 

 least on the north shore. In the deepest parts of the 

 river, on the south shore, between Anticosti and part of 

 the Gaspe Peninsula, the thermometer registered a few- 

 degrees higher. Sind dredged on the north shore in 

 25 fathoms also made the mercury sink to 37° or 38". 



Many interesting Foraminifera and Sponges were ob- 

 tained, but as yet only a few of these have been examined 

 with any care. A number of Pennatuke were dredged 

 south of Anticosti ; the genus has not been previously 

 recorded, so far as I am aware, as inhabiting the Atlantic 

 coast of America. They were found in mud, at depths of 

 160 and 200 fathoms, and it seems probable that this 

 species, at least, is sedentary, and that it lives with a por- 

 tion of the base of the stem rooted in the soft mud. Ac- 

 tinia ciiaulhus and Tcalia crassicoDiis were frequent in 

 200 to 250 fathoms. The Echinodcrms characteristic of 

 the greater depths are a Spatani^iis (specifically distinct 

 from the common British species), Ctciiodiscus crispatiis, 

 Ophioglypha Sa'si/ (very large), Ophiacaiitha spiiiidosa, 

 and Ainphiiira HotboUii. Marine worms, of many genera 

 and species, were both numerous and fine. Among the 

 more interesting oflhe Crustacea were A3'OT//to«_^AOj.f//,'j(?) 

 and a species of Pycnogonuin. Several of the last named 

 Crustaceans were taken at a depth of 250 fathoms, en- 

 tangled on a swab, fastened in front of a deep-sea lead, 

 which was attached to the rope, a few feet from the 

 mouth of the dredge. This circumstance tends to show 

 that the genus is not always parasitic in its habits. The 

 Decapods, Amphipods, S^c, at least those of greatest in- 

 terest, have not yet been identified. Among the most 

 noticeable of the marine Pol)zoa are DcJ'rancia tniiuata, 

 and what appears to be a Rctcpora. Not many species 

 in this group were obtained in very deep water, and those 

 procured were, for the most part, of small size. About 

 six species of Tunicates were collected. Being anxious to 

 have Mr. J. Gwyn Jeffreys' opinion upon the various 

 species of Mollusca during his visit to Montreal, I studied 

 these carefully fiist, and submitted the whole of them to 

 him for examination. Twenty-four species of Testaceous 

 Molhtsca were obtained at depths of from 90 to 250 

 fathoms. Nearly all of these are Arctic forms, and eleven 

 of them are new to the continent of America. 



The following are some of the most interesting of 



