46 



SCIENCE. 



[Vol. X. No. 233 



with a few hundred pounds of sand. If the envelope were abso- 

 lutely tight, this would be ample for several ascents to 10,000 feet, 

 or to keep the balloon in suspension many days. Nothing of 

 scientific accuracy can be had at a high level without a practised 

 hand on the spot. Questions of exposure of instruments, observa- 

 tions of clouds, etc., demand an immediate answer at each record, 

 if we desire valuable observations. Glaisher made thousands of 

 observations of the moisture-contents of the air in his memorable 

 scientific ascents, but, though these have been utilized by others in 

 doubtful computations, he himself does not summarize them in 

 considering his results. All who have tried to make humidity-ob- 

 servations in a room, with no air stirring (which is precisely the 

 condition in a balloon), know how exceedingly unsatisfactory 

 they are. 



I believe that the investigations needed may be made at an ex- 

 pense much less than is ordinarily supposed. There is needed a 

 balloon of about 60,000 cubic feet capacity (a larger one would be 

 too unwieldy, and is not necessary for ascents up to 20,000 feet). 

 The gas for inflation should be the last that comes in the process 

 of manufacture : this is poor in illuminating power, because it has 

 less carbon, but it is nearly one-fourth more buoyant than ordinary 

 coal-gas. This is not exactly a refuse product, yet it can be had 

 vei-y cheaply. It would be a most excellent plan to send up four 

 balloons at once, about two hundred miles from the centre of a 

 storm, in the north-east, north-west, south-west, and south-east 

 quadrants. But, as this would be rather expensive, we must ex- 

 plore the most interesting point first. I would send up the balloon 

 either to the south-west or west of a storm : at a height of 6,000 

 feet, it would, in all probability, outstrip the storm, and the descent 

 could be made either in the centre or a little to the east of it. We 

 could then either make another ascent immediately, or wait till the 

 storm has passed overhead, and then make another trip just as at 

 first. This will enable us to determine, not only the vertical dis- 

 tribution of temperature and moisture in the neighborhood of the 

 storm, but also the action, whirling or otherwise, that takes place 

 at the seat of the storm, or where the ' power ' of the storm is de- 

 veloped. When the balloon is no longer able to rise, a fresh 

 supply of gas may be carried to it in a small balloon, or in a long 

 flexible cylinder (as suggested by Professor King). If near any 

 gas-works, the balloon may be towed near enough to obtain a 

 fresh supply. As about 30,000 feet of gas would be needed to float 

 the balloon and all its appliances, it will be seen that this would 

 effect a great saving. I understand perfectly that cariying out 

 such suggestions as these may be a very difficult matter in practice, 

 and often impossible in a high wind. For ten thousand dollars, I 

 think, fifty or sixty ascents might be made, which would be of in- 

 calculable importance in the study of the origin, development, and 

 progress of storms. Such investigation is absolutely necessary if 

 we would advance our knowledge of the generation of storms. 

 Any advance in this direction is of such moment to almost all 

 classes of people, especially to farmers and mariners, that we may 

 hope such a small sum will be volunteered, or obtained from gov- 

 ernment, ere long for this study. H. Allen Hazen. 



Washington, D.C., July 19. 



Cloud-Heights. 



The following method, which can often be used to determine the 

 elevation of certain clouds, may interest some of your readers, par- 

 ticularly topographers and meteorologists. 



I was watching to-day, from Little Monadnock, the shadow of a 

 dense cumulus moving slowly along the southern slope of Monad- 

 nock, until finally the edge touched the hotel about half-way up 

 the mountain. It occurred to me, that, if the point where I stood 

 and the hotel were plotted on a plane-table sheet, and the sheet 

 oriented, the elevation of the cloud could easily be found in this way 

 At the moment the shadow reaches the second plotted position, 

 draw, through the station occupied by the observer, a line, and read 

 a vertical angle to the edge of the cloud that casts the shadow. Then, 

 through the second plotted position, draw a line in the direction of 

 the sun. The point of intersection of these two lines is the hori- 

 zontal projection of the position of a point on the edge of the cloud 

 at the time the shadow has reached the second plotted position. 

 The distance (to be scaled from the map) from this intersection to 



the point occupied, is the base, and the vertical angle of elevation 

 the adjacent angle of a right-triangle, of which the altitude is the 

 height of the cloud above the observer. This may be corrected for 

 curvature and refraction. 



When a plane-table sheet is nearly complete, with many located 

 points on it, the same cloud may be observed several times, and the 

 determinations of altitude compared. 



This method is extremely simple, and I am very anxious to have 

 it tried. I shall not be able to do this myself for several weeks, 

 but I hope some one who is working with a plane-table will, and 

 let me know his results. H. L. SMYTH. 



Dublin, N.H., July 2. 



The Wholesomeness of Swill-Milk. 



The discussion carried on in the pages of Science for some 

 weeks past upon the healthfulness of milk from cows fed upon 

 distillery-swill has, in my opinion, failed to definitely settle the ques- 

 tion. There can be no doubt of the vital importance of the matter, 

 and all physicians and sanitarians will agree that a solution of the 

 problem is highly desirable. 



1. I venture to say that no positive evidence has been submitted 

 showing any ill effect of swill upon cows fed with it. The evils 

 attributable to it are largely, if not entirely, to be ascribed to the 

 unsanitary surroundings of the animals. 



2. Whatever evidence has any positive value indicates that swill 

 is equally as good and proper food (used with judgment) as hay, 

 dried fodder, ensilage, or bulbous roots. These all differ widely 

 in chemical composition from the green foods (grass, clover, green 

 oats, and corn), which may be looked upon as the normal food of 

 cows. 



3. It may be worth while remembering that lactation in a dairy 

 is not a normal process. Dairy-cows are ' milk-machines.' The 

 dairy business would not be very profitable if lactation were not 

 forced to some degree. 



4. Experienced agriculturists, like Professor Armsby and Dr. 

 Sturtevant (Science, ix. pp. 602 - 3), have failed to see any ill effects 

 attributable entirely to swill, and such veterinarians of ability as 

 Professor Law and Dr. Salmon (Ibid, p. 552) corroborate this testi- 

 mony. 



5. The facts collated by Professor Brewer (Ibid, p. 550), showing 

 the ready absorption of germs and odors by milk, the transmission 

 of the flavor of various odoriferous substances eaten by the animal 

 to the secretion, the passage of certain drugs administered medicin- 

 ally into the milk of nursing women, or the notorious fact that 

 swill-milk stable? are 'proverbially foul and stinking,' have no bear- 

 ing upon the case. The evidence required to establish the un- 

 wholesomeness of swill as food for milk-giving animals must be of 

 a different character. 



6. While it may be conceded that ' chemical analyses will not 

 settle the question ' of the wholesomeness of swill-milk, the fact 

 remains that we have at present no other way of determining the 

 physical qualities of a specimen of milk. Bacteriological investiga- 

 tion may determine the presence of the germs of tuberculosis, 

 typhoid, and, in view of recent discoveries, of scarlet-fever, but will 

 not enable us to ascertain the relative proportions of saccharine, 

 fatty, aqueous, or proteid matters present. Chemistry is here still 

 our main-stay, and, other things being equal (more definitely, disease- 

 germs being absent), a specimen of milk nearly approaching the 

 chemical standard established by Koenig may be looked upon as a 

 wholesome food. Other factors besides the food of the animal 

 enter into the production of milk. The age of the animal, period 

 of lactation, time when the milk is drawn, and general sanitary 

 condition, must not be ignored. 



7. The asserted greater firmness, and consequent indigestibility, 

 of the coagulum in swill-milk is not based upon a sufficient number 

 of observations to admit of unquestioned acceptance. It should 

 be easy to determine this in any chemical laboratory. No single 

 series of observations would decide this, however. It would be 

 necessary to test milk from cows fed upon swill but kept under 

 good sanitary conditions, side by side with milk from animals kept 

 under the ordinary conditions of city stable-hfe, and fed upon 

 various foods. 



8. A scientific solution of the question will not be furthered by 



