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34 left of the magnetic line and drawing our curve through that point, count off 10 spaces, if doubling is desired, or 15 spaces if trebling, and draw the curve as in the ordinary method. This distortion should always _ be kept in- mind when working withthe © Gata aiter the curve. is plotted. Objection is sometimes made by a few of our best educated officers that they prefer to trust to a paper, pencil and their own figures rather than to any mechanical method of solving problems. There is no man who is so infallible in his calcula- tions that a check is never necessary; and for the purpose of a check the device is invaluable to such naviga- fors. We havee all had the - ex- perience of making a mistake in add- ing a column of figures and being un- able to discover it. But. the adding machine. never adds incorrectly, and what banking house or large com- mercial house is to-day without one of these valuable little mechanical devices? BAXTER'S COMPASS DIAGRAM This device consists of a diagram of little squares, each one of which is equivalent to one degree on.the compass. In length there are 360 of these degree squares. The left hand margin of the diagram, which is Some 22 in: in lenbth by 5- in. i. width, is marked .by the com- pass points, and fractional points, the card being straightened out in- stead of circular. The small squares representing degrees are made to co- incide with their equivalent in points and fractional points on this margin; that is, North and South are marked zero, and East and West 90°, hence degrees may be readily converted into compass points or fractions there- of, and vice versa, compass into degrees. The diagram is formed _ by horizontal and vertical lines. At each five degrees the lines are drawn heavy and those between them are made lighter. These lines are num- bered according to the number of. degrees they represent on the com- pass card. The vertical line in the center of the. diagram, which 'separates the two sections of the card represents the magnetic line, and is _ marked zero on the horizontal. In fact the circular card of the compass 'is laid out into squares and straight lines instead of spherical. The cor- rection of courses and bearings, and the finding of the deviation is per- formed by mere inspection, or by method of construction, no calcula- tion by figures is necessary beyond reading from the scale; hence all cal- points TAE MARINE REVIEW culations are performed by the card itself. The only instrument to be used in connection with the card is an isosceles right-angled triangle, made of transparent celluloid, and is called the corrector. angle is precisely the same width as that of either section of the diagram. When the base line of the corrector (triangle) is laid parallel with a horizontal line of the diagram, the hypotenuse of the corrector cuts each one of- the little squares represent- ing degrees into its own figure, or shape, that is, 'an isosceles right- angled triangle; in other words the whole thing solves itself into isosceles right-angled triangles. Then which- ever way the corrections are to be applied, whether to the right or to the left (easterly or westerly) de- pends upon which angle of the cor- rector you use fora starting. -pdint. From this it must be observed that the diagram and corrector perform the operation of simple addition and subtraction, by. construction, since the triangles passed over by the edge of the corrector are all equal. The diagram may also be used for laying down the deviation curve after it has been found for ship's head on different points. The great advan- tage of this is that the deviation does not have to be found for. an exact point of the compass, so long as these points are not too far removed from each other. There are' various "graphic methods" of this nature on the market, but this method seems peculiarly adapted for this ° purpose. It requires no calculation and only a moderate degree of neat-handiness. The method consists of two parts, the diagram and the curve. The dia- gram is the same for all vessels. BOOK REVIEW. Lake Pilots' Handbook is a new lake publication compiled by Capt. George 'Trimble, of Port Huron, Mach =~ The ook is devoted to a general information on the subject of the great Jakes, For years the cap- tain has been an enthusiastic collector - Of Martine books and papers, and from them he has culled all 'the valu- able information that should be of interest to the lake sailor. The first pages of the book are devoted to a history of the great lakes; the build- ing of the first sailing and also the first steam vessels on these waters. A description of the lakes and their connecting rivers and canal systems is given some space. The lighthouses, the steamboat inspection, the life sav- The base of this tri- ing, the weather bureau, the marine hospital, the marine postal, hydro- graphic office and lake survey ser- "vices all come in for some attention. A list with addrésses of all the lake associations and unions is printed; also the laws regarding licensed ofh- cers of steamers of the lakes, together with a synopsis of the navigation laws of those states bordering on the lakes. Pilot rules. for the great lakes and connecting rivers are repro- duced in full; United States and Ca- nadian stotm signal systems; bridge signaling for the various ports 'on the lakes, dry dock system, popula- tions of lake cities and towns, land matks on Lake Superior, ete. About a dozen pages are devoted to "things wotth knowing.' Beatings of piers and breakwaters, distance tables for the lakes and rivers, distances by various routes, life saving stations, fog whistles, lighthouses, depths of water in the smaller harbors, are all given considerable space and atten- tion. A small portion of the book is devoted to the science of lake navigation, but only in a smattering way. The last part of 'the book is devoted to miscellaneous -- subjects, such. as. Sailors'. Phrases, --Waves, Depths of the Ocean, Steam, Horse- power of Engines and Boilers, Knots of All Kinds, Rules of Arithmetic, ete, etc... [here is. bat ver little in the book that is original, but since the publication is more on the compilation order this should not be. expected. More of the book should have been devoted to the modern practices of lake navigation. The two best things in the book, accord- ing to our way of -thinkitfg, are the articles on "Government Soundings" and "The Barometer." These are really live issues, and are instructive. The price of the book and where to get it will be advertised later on. It is reported to the United States Lake Survey that the steamer Algonquin, Capt. John Williams, master, struck some submerged obstacle off Whitefish Point, Lake Superior, on May 26. On June 27 the mate of the Algonquin sighted what he took to be the same construction about 5 miles SE by E % E from White- fish Point, and estimated it had drifted 4 or 5 miles since the previous striking. It appeared to bea portion of a wooden vessel with spar projecting about 4 feet above water surface. As the Algonquin was considerably damaged by the col- lision, masters are warned to be on the lookout for the obstruction, and if sighted to report the same promptly to the Lake "Survey Office, Detroit: