April i8, 1901] 



NATURE 



601 



a larger share in all works undertaken to promote the welfare 

 of their country. 



The author does not claim to be a botanist, nor does Dr. 

 Schlich, who preceded Mr. Ribbentrop, nor does their successor, 

 Mr. H. C. Hill, the present Inspector-General of Forests. It 

 is necessary to mention this because in England, also among 

 scientific men, the opinion prevails that forestry is a branch 

 of botany, and that a forester who is not a botanist cannot 

 claim to be a scientific man. Dr. Schlich's great merit while 

 holding the appointment in India was to organise that branch 

 of forestry which deals with the plans regulating the working of 

 the forests, a business which is based more upon mathematics 

 than upon botany. Mr. Ribbentrop's great achievement has 

 been to study and correctly to appreciate the peculiar sylvi- 

 cultural requirements of the great variety of trees and bamboos 

 with which the forester has to deal in India. Through his 

 labours the management of teak, of sal, sissoo, deodar, and of 

 other important trees when growing by themselves or in company* 

 with other kinds or with bamboos, their regeneration, natural or 

 artificial, and their subsequent treatment under different condi- 

 tions of soil and climate, is much better understood now than it 

 was twenty years ago. These are great results, which, provided 

 no retrograde measures are adopted, will bear fruit in steadily 

 increasing the productive powers and capital value of the forests, 

 and will contribute largely to the welfare of the millions 

 inhabiting the British Indian Empire. 



Dietrich Brandis. 



SUBMARINE BOATS. 

 'T^HE building of five submarine boats for the British Navy 

 ■*■ not only forms quite a new departure but also, perhaps, the 

 advent of the nucleus for an instrument of war of novel design. 

 The boats (says Engineering, March 29), which are being built 

 by Messrs. Vickers, Sons and Maxim, Ltd., are of the Holland 

 improved type and are 63 ft. 4 in. in length over all, 1 1 ft. 9 in. 

 beam, and 120 tons displacement submerged, and they will be 

 capable of expelling torpedoes either with the boat at rest, during 

 the run on the surface, or steaming at any speed submerged. 

 When running on the surface the boats will be propelled by a 

 gasoline engine (of marine type, inverted, and with four single 

 acting cylinders). The amount of fuel carried will sufiice for a 

 run of about 400 miles with a maximum speed of about 9 knots, 

 and when submerged an electric motor of the waterproof type, 

 worked with stor^e batteries, will give the vessel a speed of 

 seven knots, which can be maintained for four hours. The 

 general operation of the boat is given as follows : — " Before it 

 is desired to make a dive, the boat is brought to ' awash' con- 

 dition, with only the conning tower ports above the water. 

 The dive is then made at a small angle until the proper depth 

 is reached, when by automatic means the boat is brought to a 

 horizontal position. After the discharge of the torpedo from the 

 fixed bow tube, the compensation for the weight of the torpedo 

 is made automatically, causing only a slight change of trim for 

 a few seconds. Provision is made for quick rising and diving, 

 the time of appearance of the conning tower above the water being 

 dependent on the skill of the navigator." In the United States 

 Navy the Holland has undergone most exacting trials and has 

 proved herself " stable in service working," and it is here we 

 get the most convincing testimony, where Admiral Hitchborn, 

 chief constructor in the United States Navy, states in his official 

 report, " The v^i^/Zawrf has shown herself capable of such com- 

 plete control in the vertical plane that she may be kept within 

 a few inches of any desired depth while moving, or brought to 

 the surface and taken under again in a very short time : her 

 direction and control in the horizontal plane on the surface is 

 effected with the same facility as any other craft, and submerged 

 is limited only by the difficulties of vision : her crew are pro- 

 vided for on board with reasonable comfort and perfect safety for 

 such periods as she may be in service and working either upon 

 the surface or submerged ; and her armament, consisting entirely 

 of torpedoes, gives her great offensive power." 



THE CURRENTS IN THE GULF OF ST. 



LA WRENCE. 

 TN a former article (January 24, 1901, p. 311) we gave a 

 ■*■ summary, from a pamphlet recently issued, on the currents 

 in the Gulf of St. Lawrence, in which we noticed some points 

 of general application to similar researches elsewhere. This 

 pamphlet, issued by the Department of Marine and Fisheries, 

 NO. 1642, VOL. 63] 



Canada, gives concisely the results of investigations in the 

 summer seasons of three years in that Gulf, conducted by Mr. 

 W. Bell Dawson, in charge of the Survey of Tides and Currents. 

 It is primarily for the benefit of practical seamen ; but it also 

 contains an explanation of the hydrography of the Gulf, on 

 which this Survey has thrown considerable light ; and it is this 

 part that we now summarise. 



General Characteristics of the Gulf of St. Lawrence. — With 

 the exception of the currents in the various straits and near the 

 heads of the bays, the currents met with in the open Gulf seldom 

 exceed one knot. They are, therefore, the more easily influenced 

 by strong winds, especially at the surface of the water. Currents 

 which have a greater speed than this are found in Belle Isle and 

 Cabot Straits, in Northumberland Strait, off the Gapse coast, 

 in the Gut of Canso, and locally in channels between islands 

 and at the mouths of rivers. 



The water of the Gulf may be roughly divided by a line running 

 from South-west Point of Anticosti to the middle of Cabot 

 Strait. Along the south-western side of this line the water has 

 a lower density, as it is apparently made a little fresher by the 

 outflow of the St. Lawrence River. To the north-east of this line, 

 throughout the north-eastern arm of the Gulf, the water has the 

 same density as in the open Atlantic. 



The general drift of this water of lower density is outward, 

 towards the Atlantic. This gives rise to two constant currents, 

 one at the mouth of the St. Lawrence along the Gaspe coast) 

 which may be called the '* Gaspe Current," and the other on 

 the west side of Cabot Strait around Cape North, which may be 

 called the "Cape Breton Current." A third constant current 

 is found on the west side of Newfoundland, making north- 

 eastward from the Bay of Islands towards Rich Point. 



It is to be noted that in calling these currents constant it is only 

 meant that they usually or most frequently run in the one direc- 

 tion. During certain winds they may be much disturbed, or their 

 direction may even be reversed. 



Temperature. — It appears that in general the temperature of 

 the surface water merely rises with the progress of the season ; 

 and it is also natural that the water should become warmer to a 

 greater depth as the season advances. Even this has its 

 limitations, however ; as at a depth of 50 fathoms no greater 

 rise in temperature has yet been found than from 32" to 34°, 

 between the month of June and the end of September. 



At all three angles of the Gulf it was found that the coldest 

 water forms a layer between the depths of 30 and 50 fathoms. 

 In the vicinity of Belle Isle Strait, the same low temperatures 

 are also found at these depths ; although there the temperature 

 towards the surface is relatively lower, as a rule, than in other 

 regions. It is probable that this cold layer extends very 

 generally over the Gulf area. Below this cold layer, in the deep 

 channel of the Gulf, the teinperature from 100 to 200 fathoms is 

 found to range very constantly from 38° to 41°. This result was 

 obtained in Cabot Strait, and also between the Gaspe coast and 

 Anticosti, 220 miles further in from the Atlantic, along the deep 

 channel. This deep channel runs into the Gulf from the 

 Atlantic basin through Cabot Strait, and maintains a continuous 

 depth of some 200 fathoms across the middle of the Gulf to the 

 mouth of the St. Lawrence River. It still has a depth of 100 

 fathoms half-way up the estuary on the Lower St. Lawrence. 



Density. — It may be stated broadly that throughout the 

 north-eastern portion of the Gulf the average surface density 

 ranges from i '0235 to nearly I '0245 ; while in the south- 

 western portion the density is below 1*0235, ranging usually 

 down to I '0220, and falling in the Gaspe Current itself to i •0210. 

 The dividing line between these two portions of the Gulf runs 

 approximately from South-west Point, Anticosti, to a point in 

 the middle of Cabot Strait. The densities in the border region 

 near this dividing line naturally vary to some extent. The 

 density of the north-eastern portion is practically the same as in 

 the open Atlantic, as it was there found to range from i '0237 

 to I '0242, as shown by seven determinations made at the end of 

 June off the south and south-east coasts of Nova Scotia. 



This result is important in showing that the lower densities 

 found in the south-western portion of the Gulf of St. Lawrence 

 are confined to that side ; and this also accords with the con- 

 clusion that the general set or drift across the Gulf is in the 

 direction of a line from Gaspe to Cape Breton. On the other 

 hand, the endeavour to obtain some differences locally, which 

 would correspond with the various directions of the current, was 

 without result ; although a large number of temperatures as 

 well as densities were taken for this purpose. 

 The deep water as found from samples taken at depths of 100 



