The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE
OMB APPROVAL
OMB Number: 3235-0006
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COLUMN 1 COLUMN 2 COLUMN 3 COLUMN 4 COLUMN 5 COLUMN 6 COLUMN 7 COLUMN 8
VALUE SHRS OR SH/ PUT/ INVESTMENT OTHER VOTING AUTHORITY
NAME OF ISSUER TITLE OF CLASS CUSIP FIGI (to the nearest dollar) PRN AMT PRN CALL DISCRETION MANAGER SOLE SHARED NONE
Abbvie Inc. COM 00287Y109   2,302 14,243 SH   SOLE   0 0 14,243
Adobe COM 00724F101   10,405 30,919 SH   SOLE   0 0 30,919
Advanced Micro Devices Inc COM 007903107   367 5,665 SH   SOLE   0 0 5,665
Air Products COM 009158106   17,781 57,681 SH   SOLE   0 0 57,681
Alcon COM h01301128   16,426 239,628 SH   SOLE   0 0 239,628
Alphabet Inc Cap Sk Cl A COM 02079K305   1,337 15,150 SH   SOLE   0 0 15,150
Alphabet Inc Cap Sk Cl C COM 02079k107   367 4,140 SH   SOLE   0 0 4,140
Amazon COM 023135106   9,782 116,449 SH   SOLE   0 0 116,449
Amphenol COM 032095101   14,380 188,858 SH   SOLE   0 0 188,858
Apple COM 037833100   47,787 367,793 SH   SOLE   0 0 367,793
Automatic Data Processing COM 053015103   45,250 189,442 SH   SOLE   0 0 189,442
Bank Of America Corporation Ne COM 060505104   210 6,342 SH   SOLE   0 0 6,342
Becton Dickinson COM 075887109   21,140 83,131 SH   SOLE   0 0 83,131
Berkshire Hathaway Cl B COM 084670702   572 1,852 SH   SOLE   0 0 1,852
Black Stone Minerals L Com Uni COM 09225m101   2,404 142,512 SH   SOLE   0 0 142,512
Blackstone Inc Com COM 09260D107   375 5,055 SH   SOLE   0 0 5,055
Bristol Myers Squibb COM 110122108   476 6,615 SH   SOLE   0 0 6,615
Chevron Corp COM 166764100   1,598 8,905 SH   SOLE   0 0 8,905
Chipotle Mexican Grill Com COM 169656105   277 200 SH   SOLE   0 0 200
Cintas COM 172908105   20,505 45,404 SH   SOLE   0 0 45,404
Coca-Cola COM 191216100   27,192 427,479 SH   SOLE   0 0 427,479
Colgate Palmolive COM 194162103   227 2,877 SH   SOLE   0 0 2,877
Conocophillips COM 20825C104   555 4,703 SH   SOLE   0 0 4,703
Costco Whsl Corp New COM 22160K105   210 461 SH   SOLE   0 0 461
Cullen Frost Bank COM 229899109   242 1,807 SH   SOLE   0 0 1,807
Cvs Health COM 126650100   333 3,571 SH   SOLE   0 0 3,571
Danaher Corp COM 235851102   502 1,891 SH   SOLE   0 0 1,891
Donaldson COM 257651109   30,506 518,193 SH   SOLE   0 0 518,193
Dorchester Minerals Lp COM 25820R105   1,569 52,423 SH   SOLE   0 0 52,423
Dover COM 260003108   28,807 212,738 SH   SOLE   0 0 212,738
Ecolab COM 278865100   23,839 163,775 SH   SOLE   0 0 163,775
Emerson Electric COM 291011104   26,797 278,962 SH   SOLE   0 0 278,962
Exxon Mobil Corp COM 30231g102   5,446 49,371 SH   SOLE   0 0 49,371
FedEx COM 31428x106   20,338 117,422 SH   SOLE   0 0 117,422
First Financial Bankshares COM 32020R109   252 7,336 SH   SOLE   0 0 7,336
Home Depot COM 437076102   690 2,183 SH   SOLE   0 0 2,183
Honeywell International COM 438516106   27,438 128,034 SH   SOLE   0 0 128,034
Illinois Tool Works COM 452308109   38,830 176,258 SH   SOLE   0 0 176,258
Intel COM 458140100   14,147 535,266 SH   SOLE   0 0 535,266
International Business Machine COM 459200101   474 3,365 SH   SOLE   0 0 3,365
Intuit COM 461202103   14,839 38,125 SH   SOLE   0 0 38,125
Intuitive Surgical COM 46120e602   17,943 67,622 SH   SOLE   0 0 67,622
Ishares Tr S&p Midcap 400 COM 464287507   312 1,288 SH   SOLE   0 0 1,288
Johnson & Johnson COM 478160104   32,098 181,702 SH   SOLE   0 0 181,702
Jp Morgan Chase & Co COM 46625H100   1,098 8,188 SH   SOLE   0 0 8,188
Lam Resh Corp COM 512807108   719 1,711 SH   SOLE   0 0 1,711
Linde Plc Com COM G5494j103   297 912 SH   SOLE   0 0 912
Lowes Cos Inc COM 548661107   839 4,211 SH   SOLE   0 0 4,211
Mastercard Inc Cl A COM 57636q104   1,747 5,025 SH   SOLE   0 0 5,025
McCormick COM 579780206   19,028 229,558 SH   SOLE   0 0 229,558
Mcdonald's Corp. COM 580135101   310 1,175 SH   SOLE   0 0 1,175
Medtronic Plc COM g5960l103   642 8,260 SH   SOLE   0 0 8,260
Merck & Co Inc COM 58933Y105   584 5,265 SH   SOLE   0 0 5,265
Microsoft COM 594918104   74,025 308,668 SH   SOLE   0 0 308,668
Mondelez Intl Inc Cl A COM 609207105   441 6,610 SH   SOLE   0 0 6,610
National Instruments COM 636518102   16,346 442,980 SH   SOLE   0 0 442,980
Netflix Inc COM 64110L106   300 1,017 SH   SOLE   0 0 1,017
Nike COM 654106103   328 2,804 SH   SOLE   0 0 2,804
Nokia COM 654902204   61 13,126 SH   SOLE   0 0 13,126
Nordson COM 655663102   52,081 219,084 SH   SOLE   0 0 219,084
Novartis Ag COM 66987V109   1,061 11,698 SH   SOLE   0 0 11,698
Nvidia COM 67066G104   454 3,105 SH   SOLE   0 0 3,105
Paccar COM 693718108   25,645 259,118 SH   SOLE   0 0 259,118
Paypal COM 70450Y103   308 4,330 SH   SOLE   0 0 4,330
Pepsico COM 713448108   31,198 172,688 SH   SOLE   0 0 172,688
Pfizer COM 717081103   219 4,265 SH   SOLE   0 0 4,265
Procter & Gamble COM 742718109   31,597 208,478 SH   SOLE   0 0 208,478
S&p Global Inc COM 78409v104   352 1,051 SH   SOLE   0 0 1,051
Sabine Royalty Trust Ubi COM 785688102   1,196 14,000 SH   SOLE   0 0 14,000
Salesforce Inc. COM 79466L302   222 1,676 SH   SOLE   0 0 1,676
San Juan Basin Royalty Trust COM 798241105   9,277 812,306 SH   SOLE   0 0 812,306
Select Sector Spdr Tr Sbi Int- COM 81369y886   238 3,373 SH   SOLE   0 0 3,373
Spdr Gold Trust Gold Shs COM 78463v107   450 2,650 SH   SOLE   0 0 2,650
Stryker COM 863667101   15,650 64,009 SH   SOLE   0 0 64,009
Sysco Corp COM 871829107   383 5,013 SH   SOLE   0 0 5,013
Taiwan Semiconductor COM 874039100   21,905 294,069 SH   SOLE   0 0 294,069
Telefonica de Espana COM 879382208   50 13,916 SH   SOLE   0 0 13,916
Thermo Fisher COM 883556102   13,881 25,206 SH   SOLE   0 0 25,206
Tractor Supply Co COM 892356106   426 1,891 SH   SOLE   0 0 1,891
Union Pacific Corp. COM 907818108   315 1,520 SH   SOLE   0 0 1,520
United Parcel Service COM 911312106   4,613 26,537 SH   SOLE   0 0 26,537
Unitedhealth Group COM 91324P102   1,093 2,061 SH   SOLE   0 0 2,061
Vanguard FTSE Developed Market COM 921943858   309 7,372 SH   SOLE   0 0 7,372
Vanguard Index Fds Reit Viper COM 922908553   489 5,931 SH   SOLE   0 0 5,931
Vanguard Index Fds S&p 500 Etf COM 922908363   882 2,509 SH   SOLE   0 0 2,509
Visa Inc-Class A Shrs COM 92826C839   455 2,190 SH   SOLE   0 0 2,190
W.W. Grainger COM 384802104   211 380 SH   SOLE   0 0 380
Walt Disney COM 254687106   376 4,327 SH   SOLE   0 0 4,327
Waste Management Inc Del COM 94106L109   549 3,500 SH   SOLE   0 0 3,500