310 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



rOcTOBER, 



there may have been, is, therefore, to be attributed in a general view of the 

 subject to the capitalization of loans and the creation of fictitious capital by 

 the purchase of railways at premiums, and, therefore, at sums beyond what 

 they actually cost. These being profitable speculations when shares were 

 high, were pushed to such an extent as now to press severely on the original 

 share capital of railway companies. The great evil of the last three years is 

 the extravagant outlay of money which has taken place ; an outlay which, 

 instead of being checked by the legislature, has been encouraged to the 

 utmost by the mode of inquiry adopted. This has inflicted on the railway 

 system a burden which it will never be able to throw off, and which the 

 public will always have to bear with them in a higher rate of charge for 

 conveyance than wonid with common prudence have been necessary. It 

 only remains to stop the extravagance with a strong hand. The very 

 existence of the railway companies depends on the economy they can prac- 

 tise in making and working their railways ; and nothing which on the face 

 of it involves increased outlay, be it diversity of gauge and its consequence 

 the mixed gauge, or the more plausible plea of competition, should be coun- 

 tenanced either by railway companies or by the legislature, if we wish to 

 secure for ourselves the full fruits of that admirable invention which England 

 and English engineers who have followed in the steps of George Stephenson 

 have given to the world. 



A.VEMOMETRy. 



" Report of further progress of Anemometrical Researches." By Pro- 

 fessor Phillips. 



Referring to the report on this subject presented to the Southampton 

 Meeting, the author recapitulated the steps of the investigation by which he 

 had been conducted to propose the evaporation of water as a measure of 

 the velocity of air-movement. In the former researches, the conclusion 

 which may be drawn a priori from Dr. Apjohn's formula for the relation of 

 the temperature of the dew point to that of an evaporating surface was 

 verified ; and the rate of cooling of a wet bulb in the open air was found to 

 be cat. par. simply proportional to ^ — t' (t being the temperature of the 

 air, I' that of an evaporating surface). The air-movement was found to 

 affect the rate of cooling nearly in proportion to the square root of the 

 velocity ; and thus by simply observing the rate of cooling of a wet bulb 

 exposed to a current of air, and also the value o{ t — t', the velocity of the 

 air current becomes easily calculable. But this instrument is only an ane- 

 moscope, of extreme dehcacy and various applicability indeed, hut incapable 

 of being converted to a self-registering anemometer. — It appeared to the 

 author probable that the rale of evaporation followed nearly or exactly the 

 same law as the rate of cooling, — the same reasoning in fact applying to 

 each case. This was tested by experiment in a great variety of ways, with 

 instruments of extremely various forms, and with velocities of air-movement 

 from 400 yards to 27,000 yards in the hour. The velocities of the wind 

 were measured by a very lightly-poised machine anemometer of Dr. Robin- 

 son's construction, but without any wheel-work, the revolutions being 

 counted by the observer. — In the course of these experiments some appa- 

 rently anomalous circumstances in the rate of evaporation occurred to the 

 author ; hut these he hopes to be able to interpret by further careful re- 

 search, and finally to present in the compass of a few cubic inches an anemo- 

 meter specially suited to measure and record the low velocities of wind, and 

 furnish a useful complement to the larger machines already esteemed to be 

 so impoitaut in meteorology. 



Height of Waves. 



" On the Velocity and Height of Waves," as observed by Capt. Stanley; 

 being the result of experiments made on board H.M.S. Rattlesnake. 



The method adopted for the determination of the length and speed of the 

 sea was to veer a spar astern by the marked lead line, when the ship was 

 going dead before the wind and sea, until the spar was on the crest of one 

 wave, while the ship's stern was on the crest of the preceding one. After a 

 few trials, it was found that when the sea was at all regular, this distance 

 could be obtained within two or three fathoms, when the length of wave was 

 50. In order to ascertain the speed of the sea, the time was noted when 

 the crest of the advancing wave passed the spar astern, and also the time 

 when it reached the ship ; and by taking a number of observations, there 

 is every reason to believe results have been obtained not very far from the 

 truth. The officer noting the time in all these observations having only to 

 register the indications of the watch when the observer called " Stop," had 

 no bias to induce him to make the differences more regular. For measuring 

 the height of the waves, a plan recommended by Mrs. Somerville was 

 adopted — which Capt. Stanley has tried for ten years with great success. 

 When the ship is in the trough of the sea, the person observing ascends the 

 "gging until he can just see the crest of the coming wave on with the hori. 

 zon, and the height of his eye above the ship's water-line will give a very 

 fair measure of the difference of level between the crest and hollow of a sea. 

 Of course, in all these observations, the mean of a great many have been 

 taken ; for even when the sea is most regular, apparently there is a change 

 in the height of the individual waves. In order to show how closely the 

 different results came, observations on different days are given from which 

 they were deduced, — 



Experiment, Xo. 1. 

 Length of sea, 55 fathoms ; speed of ship, 7'2 knots ; height of wave, 22 

 feet ; time the wave took in passing from spar to stern, 10 seconds ; speed 

 of sea deduced, 27' per hour. 



Experiment, No. 2. 

 Times observed of wave 

 passiug from spar to stern. 

 Sffc. 



»7 

 7-0 

 tl-2 

 63 

 7-0 

 86 

 8-8 

 8-4 



Length of wave, 43 fathoms. 



Average height, *_'" fei't. 



Speed of stiip, l'> knots. 



Speed of wave deduced, 245 nautical miles per hour. 



t*/(i40 



8'0 Mean time of wave going from spar to stern. 



Experiment, No. 3. 



Length of wave, 50 fathoms. 



Height of wave, 20 tVet. 



Speed of flbip, fi knots. 



Speed of wave deduced, 24 nautical miles per hour. 



Sec. 



7-4 

 l.tO 

 U17 

 10-0 

 10 2 



11-0 



lO'O Mean time of wave passing from spar to stern. 



Experiment, No. 4. 

 Sec. 

 7-5 



7''i 

 nil) 



:i-ii 



90 

 Im-0 

 90 

 8-0 

 95 



9/79-0 



7*8 Mean time of wave passing from spar to stern. 



Experiment, No. 5. 

 Length of wave, 33 fathoms. 

 Speed of ship, G Ijnots. 

 Speed of wave deduced, 22' 1 nautical miles per hour. 



Experiment, No. 6. 



Length of wave, 57 fathoms, "j Sea irregular; 

 Height of wave, 22 feet. \ observations 



Speed of ship, 7 knots. J not very good. 



Speed of wave deduced, 2fJ'2 nautical miles per hour. 



Length of wave, 30 ^o 60 fathoms. 



Height of wave. — 



Speed of ship, 5 knots. 



Speed of wave deduced, 22" 1 nautical miles per hour 



6/62-5 



Sec. 

 05 

 5 

 80 

 8 5 

 7-0 

 12-5 

 W-0 



Mean time of wave going from spar to stern. 

 Experiment, No. 7. 



Length of wave, .-^5 fathoms. 



Height of wave, 17 feet. 



Speed of ship, 7-8 knots. 



Speed of wave deduced, 22 nautical miles per hour. 



7/62-0 



8-9 Mean time of sea passing from spar to stern. 

 Summary of Observations. 



Note. — The numbers denoting the strength of the wind aie those used by Admiral 

 Beaufort. 



